Sensor configuration for a materials handling vehicle

ABSTRACT

A materials handling vehicle includes a power unit, a load handling assembly, at least one first obstacle detector, and at least one second obstacle detector. The at least one first obstacle detector is mounted at a first location on the power unit to detect an object located along a path of travel of the power unit beyond a non-detect zone of the at least one first obstacle detector. The at least one second obstacle detector is mounted at a second location on the power unit, spaced from the first location in a first direction, and is capable of detecting an object in the non-detect zone of the at least one first obstacle detector.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/649,738, filed Dec. 30, 2009, entitled “APPARATUS FORREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” and acontinuation-in-part of International Patent Application Serial No.PCT/US09/69839, filed Dec. 30, 2009, entitled “APPARATUS FOR REMOTELYCONTROLLING A MATERIALS HANDLING VEHICLE,” which each claim the benefitof U.S. Provisional Patent Application Ser. No. 61/222,632, filed Jul.2, 2009, entitled “APPARATUS FOR REMOTELY CONTROLLING A MATERIALSHANDLING VEHICLE,” the entire disclosures of each of which are herebyincorporated by reference herein. This application claims the benefit ofthe filing date of U.S. Provisional Patent Application Ser. No.61/222,632 through U.S. patent application Ser. No. 12/649,738, which iscurrently pending in the United States Patent and Trademark Office. Thisapplication is also a continuation-in-part of U.S. patent applicationSer. No. 12/631,007, filed Dec. 4, 2009, entitled “MULTIPLE ZONE SENSINGFOR MATERIALS HANDLING VEHICLES,” and a continuation-in-part ofInternational Patent Application Serial No. PCT/US09/66789, filed Dec.4, 2009, entitled “MULTIPLE ZONE SENSING FOR MATERIALS HANDLINGVEHICLES,” which each claim the benefit of U.S. Provisional PatentApplication Ser. No. 61/119,952, filed Dec. 4, 2008, entitled “MULTIPLEZONE SENSING FOR REMOTELY CONTROLLED MATERIALS HANDLING VEHICLES,” theentire disclosures of each of which are hereby incorporated by referenceherein. This application claims the benefit of the filing date of U.S.Provisional Patent Application Ser. No. 61/119,952 through U.S. patentapplication Ser. No. 12/631,007, which is currently pending in theUnited States Patent and Trademark Office. This application is also acontinuation-in-part of U.S. patent application Ser. No. 12/649,815,filed Dec. 30, 2009, entitled “STEER CORRECTION FOR A REMOTELY OPERATEDMATERIALS HANDLING VEHICLE,” and a continuation-in-part of InternationalPatent Application Serial No. PCT/US09/69833, filed Dec. 30, 2009,entitled “STEER CORRECTION FOR A REMOTELY OPERATED MATERIALS HANDLINGVEHICLE,” which each claim the benefit of U.S. Provisional PatentApplication Ser. No. 61/234,866, filed Aug. 18, 2009, entitled “STEERCORRECTION FOR A REMOTELY OPERATED MATERIALS HANDLING VEHICLE,” theentire disclosures of each of which are hereby incorporated by referenceherein. This application claims the benefit of the filing date of U.S.Provisional Patent Application Ser. No. 61/234,866 through U.S. patentapplication Ser. No. 12/649,815, which is currently pending in theUnited States Patent and Trademark Office. This application is also acontinuation-in-part of U.S. patent application Ser. No. 13/011,366,filed Jan. 21, 2011, entitled “SYSTEMS AND METHODS OF REMOTELYCONTROLLING A MATERIALS HANDLING VEHICLE,” which is currently pending inthe United States Patent and Trademark Office, and acontinuation-in-part of International Patent Application Serial No.PCT/US12/22011, filed Jan. 20, 2012, entitled “SYSTEM FOR REMOTELYCONTROLLING A MATERIALS HANDLING VEHICLE,” the entire disclosures ofeach of which are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates in general to materials handling vehicles,and more particularly, to sensor configurations for detecting objects inor near a path of travel of a vehicle.

Low level order picking trucks are commonly used for picking stock inwarehouses and distribution centers. Such order picking trucks typicallyinclude load carrying forks, a power unit and a platform upon which anoperator may step and ride while controlling the truck. The power unithas a steerable wheel and corresponding traction and steering controlmechanisms, e.g., a movable steering arm that is coupled to thesteerable wheel. A control handle attached to the steering arm typicallyincludes the operational controls necessary for operating the truck,such as controls for raising and lowering the forks and for controllingthe speed and direction (forward or reverse) of the truck.

In a typical stock picking operation, an operator fills orders fromavailable stock items that are located in storage areas provided on bothsides of a plurality of aisles of a warehouse or distribution center.The operator drives a low lever order picking truck to a first locationwhere item(s) on a first order are to be picked. In a pick process, theoperator retrieves the ordered stock item(s) from their associatedstorage area(s) and places the picked stock on a pallet, collection cageor other support structure carried by the forks of the order pickingtruck. The operator then advances the order picking truck to the nextlocation where item(s) are to be picked. The above process is repeateduntil all stock items on the order(s) have been picked.

The operator normally steps onto the truck platform to ride on the orderpicking truck when the distance between consecutive picks is longer, forexample twenty or more feet (approximately 6.1 meters). Correspondingly,the operator walks alongside the truck when the distance along the routebetween consecutive picks is short. Accordingly, some order pickingtrucks include jog switches located on the truck in the vicinity of theforks and/or on or near the control handle. The jog switches can be usedby an operator walking alongside the order picking truck to acceleratethe truck to a walking speed, typically between approximately 1.6 milesper hour (3.3 kilometers per hour) to around 3.5 miles per hour (5.6kilometers per hour) to move from one stock pick location to the nextstock pick location without the need to step onto the platform of theorder picking truck. However, for such actions, the operator is requiredto interrupt picking while the order picking truck is relocated to thenext location. Thus, the operator may be required to move out of adesired working position or modify a desired walking route to reach thejog switches.

It is not uncommon for an operator to be required to repeat the pickprocess several hundred times per order. Moreover, the operator may berequired to pick numerous orders per shift. As such, the operator may berequired to spend a considerable amount of time relocating andrepositioning the order picking truck, which reduces the time availablefor the operator to spend picking stock.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, a materialshandling vehicle is provided comprising a power unit, a load handlingassembly, at least one first obstacle detector, and at least one secondobstacle detector. The at least one first obstacle detector is mountedat a first location on the power unit to detect an object located alonga path of travel of the power unit beyond a non-detect zone of the atleast one first obstacle detector. The at least one second obstacledetector is mounted at a second location on the power unit, spaced fromthe first location in a first direction, and is capable of detecting anobject in the non-detect zone of the at least one first obstacledetector.

The at least one first obstacle detector may be located at a frontportion of the power unit.

The at least one second obstacle detector may be spaced away from the atleast one first obstacle detector in a direction towards the loadhandling assembly.

The at least one first obstacle detector may comprise a sweeping lasersensor. The sweeping laser sensor may be capable of detecting an objectin any of first, second, and third zones, the first and third zonescomprising steer bumper zones used for implementing steer correctionmaneuvers and the second zone comprising a stop zone used for stoppingthe vehicle.

The at least one second obstacle detector may comprise first and secondpoint laser sensors spaced from one another in a second direction thatis generally perpendicular to the first direction. The first directionmay be a vertical direction and the second direction may be a horizontaldirection. Or, the first direction may be a horizontal direction.

According to a second aspect of the present invention, a materialshandling vehicle is provided comprising a power unit, a load handlingassembly, at least one first obstacle detector, and at least one secondobstacle detector. The at least one first obstacle detector is mountedat a first location on the power unit to detect an object located in ascan zone along a path of travel of the power unit beyond a non-detectzone of the at least one first obstacle detector, the non-detect zonebeing located between the scan zone of the first obstacle detector andthe vehicle. The at least one second obstacle detector is mounted at asecond location on the power unit spaced from the first obstacledetector in a first direction and is capable of detecting an object inthe non-detect zone.

According to a third aspect of the present invention, a materialshandling vehicle is provided comprising a power unit, a load handlingassembly, at least one first obstacle detector, and at least one secondobstacle detector. The at least one first obstacle detector comprises asweeping laser sensor mounted at a first location on the power unit todetect an object located in a scan zone along a path of travel of thepower unit beyond a non-detect zone of the at least one first obstacledetector. The at least one second obstacle detector is mounted on thepower unit below the at least one first obstacle detector and is capableof detecting an object in the non-detect zone underneath the scan zoneof the at least one first obstacle detector.

The non-detect zone may be located just in front of the vehicle andunderneath the scan zone of the sweeping laser sensor. The scan zone ofthe sweeping laser sensor may be oriented at an angle from the firstlocation toward a floor surface.

According to a fourth aspect of the present invention, a materialshandling vehicle is provided comprising a power unit, a load handlingassembly coupled to the power unit, at least one obstacle detectormounted to the power unit, and a controller. The at least one obstacledetector is provided to detect an object located along a path of travelof the power unit, the detector generating a distance signal upondetecting an object corresponding to a distance between the detectedobject and the power unit. The controller receives the distance signaland generates a corresponding vehicle stop or maximum allowable speedsignal based on the distance signal.

The materials handling vehicle may further comprise a load sensor togenerate a weight signal indicative of a weight of a load on the loadhandling assembly, wherein the controller may receive the distancesignal and the weight signal and generate a corresponding vehicle stopor maximum allowable speed signal based on the distance and weightsignals. For a given first load weight, if a sensed object is located ata distance within a first detection zone, a stop signal may be generatedby the controller to effect stopping of the vehicle. Further, for thegiven first load weight, if a sensed object is located at a distancewithin a second detection zone spaced further away from the power unitthan the first detection zone, a first maximum allowable vehicle speedmay be defined corresponding to the first load weight and an objectbeing detected in the second detection zone. Moreover, for the givenfirst load weight, if a sensed object is located at a distance within athird detection zone spaced further away from the power unit than thefirst and second detection zones, a second maximum allowable vehiclespeed greater than the first maximum may be defined corresponding to thefirst load weight and an object being detected in the third detectionzone.

According to a fourth aspect of the present invention, a materialshandling vehicle is provided comprising a power unit, a load handlingassembly coupled to the power unit, at least one obstacle detectormounted to the power unit, a load sensor, and a controller. The at leastone obstacle detector is provided to detect an object located along apath of travel of the power unit, the detector generating a distancesignal upon detecting an object corresponding to a distance between thedetected object and the power unit. The load sensor is provided togenerate a weight signal indicative of a weight of a load on the loadhandling assembly. The controller receives the distance signal and theweight signal and generates a corresponding vehicle stop or maximumallowable speed signal based on the distance and weight signals.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The following description of the preferred embodiments of the presentinvention can be best understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals, and in which:

FIG. 1 is an illustration of a materials handling vehicle capable ofremote control according to various aspects of the present invention;

FIG. 2 is a schematic diagram of several components of a materialshandling vehicle capable of remote control according to various aspectsof the present invention;

FIG. 3 is a schematic diagram illustrating detection zones of amaterials handling vehicle according to various aspects of the presentinvention;

FIG. 4 is a schematic diagram illustrating an exemplary approach fordetecting an object according to various aspects of the presentinvention;

FIG. 5 is a schematic diagram illustrating a plurality of detectionzones of a materials handling vehicle according to further aspects ofthe present invention;

FIGS. 6 and 8 illustrate a materials handling vehicle having first andsecond spaced-apart obstacle detectors;

FIG. 7 is a schematic view illustrating a materials handling vehiclehaving obstacle detectors located only at a front of the vehicle;

FIGS. 9A and 9B are views illustrating a finger-mounted remote controldevice mounted to fingers of an operator;

FIGS. 10A, 10C, 10D, and 10E illustrate various views of thefinger-mounted remote control device of FIGS. 9A and 9B;

FIG. 10B is an exploded view of the finger-mounted remote control deviceof FIGS. 9A and 9B;

FIG. 10F is a cross sectional view of the finger-mounted remote controldevice of FIGS. 9A and 9B;

FIG. 11 illustrates example lookup table data;

FIG. 12 is a flow chart of a method of implementing steer correctionaccording to various aspects of the present invention;

FIG. 13 is a schematic illustration of a materials handling vehicletraveling down a narrow warehouse aisle under remote wireless operation,which is automatically implementing a steer correction maneuveraccording to various aspects of the present invention;

FIG. 14 is a perspective view of a low level order picking truckaccording to various aspects of the present invention;

FIG. 15 is a block diagram illustrating an exemplary system for remotelycontrolling traction, steer and/or brake functions of the truckillustrated in FIG. 14 in response to wireless remote commands accordingto various aspects of the present invention;

FIG. 16 is a schematic illustration of the truck of FIG. 14 in awarehouse aisle according to various aspects of the present invention;

FIG. 17 is a schematic illustration of the truck of FIG. 14 towards theend of an exemplary warehouse aisle illustrating a disabling zoneaccording to various aspects of the present invention;

FIG. 18 is a flow chart illustrating an exemplary decision process ofthe controller on the truck of FIG. 14 according to various aspects ofthe present invention; and

FIGS. 19-20 are side and top views of a materials handling vehicleaccording to another aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the illustrated embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration, and not by way oflimitation, specific embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand that changes may be made without departing from the spirit and scopeof various embodiments of the present invention.

Low Level Order Picking Truck

Referring now to the drawings, and particularly to FIG. 1, a materialshandling vehicle, which is illustrated as a low level order pickingtruck 10, includes in general a load handling assembly 12 that extendsfrom a power unit 14. The load handling assembly 12 includes a pair offorks 16, each fork 16 having a load supporting wheel assembly 18. Theload handling assembly 12 may include other load handling features inaddition to, or in lieu of the illustrated arrangement of the forks 16,such as a load backrest, scissors-type elevating forks, outriggers orseparate height adjustable forks. Still further, the load handlingassembly 12 may include load handling features such as a mast, a loadplatform, collection cage or other support structure carried by theforks 16 or otherwise provided for handling a load supported and carriedby the truck 10.

The illustrated power unit 14 comprises a step-through operator'sstation dividing a first end section of the power unit 14 (opposite theforks 16) from a second end section (proximate the forks 16). Thestep-through operator's station provides a platform upon which anoperator may stand to drive the truck 10. The platform also provides aposition from which the operator may operate the load handling featuresof the truck 10. Presence sensors 58 may be provided, e.g., on, above,or under the platform floor of the operator's station. Still further,presence sensors 58 may be otherwise provided about the operator'sstation to detect the presence of an operator on the truck 10. In theexemplary truck of FIG. 1, the presence sensors 58 are shown in dashedlines indicating that they are positioned under the platform floor.Under this arrangement, the presence sensors 58 may comprise loadsensors, switches, etc. As an alternative, the presence sensors 58 maybe implemented above the platform 56, such as by using ultrasonic,capacitive or other suitable sensing technology.

An antenna 66 extends vertically from the power unit 14 and is providedfor receiving control signals from a corresponding remote control device70. The remote control device 70 may comprise a transmitter that is wornor otherwise maintained by the operator. As an example, the remotecontrol device 70 may be manually operable by an operator, e.g., bypressing a button or other control, to cause the device 70 to wirelesslytransmit at least a first type signal designating a travel request tothe vehicle, thus requesting the vehicle to travel by a predeterminedamount. The remote control device 70 may comprise a glove-like structure70, see FIG. 1, such as disclosed in U.S. Provisional Patent ApplicationSer. No. 60/825,688, filed Sep. 14, 2006 entitled “SYSTEMS AND METHODSOF REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S. patentapplication Ser. No. 11/855,310, entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” or U.S. patentapplication Ser. No. 11/855,324, entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” the disclosures ofeach of which are incorporated by reference herein.

The remote control device may alternatively comprise a finger-mountedremote control device 170, as illustrated in FIGS. 9A, 9B and 10A-10F.The finger-mounted remote control device 170 comprises, in theillustrated embodiment, a polymeric rigid base 172, a polymeric rigidupper housing 174 and a pivotable latch 173 coupled to the base 172 viaa generally straight spring rod 273 so as to be spring biased to ahome/locking position, as shown in FIG. 10F. The latch 173 can be movedgenerally linearly/laterally against the bias of the spring bar 273 in adirection, designated by arrow A in FIG. 10F, to a release position. Thebase and upper housing 172 and 174 are coupled together via screws 273Aand define a docking area 175 for removably receiving a wirelesstransmitter/power pack unit 176. The base and upper housing 172 and 174may alternatively be coupled together via an adhesive or an ultrasonicwelding operation. The wireless transmitter/power pack unit 176 maycomprise the components found in the communications device set out inU.S. patent application Ser. No. 11/855,324, entitled “SYSTEMS ANDMETHODS OF REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” thedisclosure of which is incorporated by reference herein. In theillustrated embodiment, a transmitter antenna is also housed in thewireless transmitter/power pack unit 176.

The wireless transmitter/power pack unit 176 is releasably held withinthe docking area 175 via the latch 173, see FIG. 10F. A contact plate178 is mounted to the base 172 via screws or pins molded into the base172 and swaged over the plate (not shown) and includes one or morecontacts (not shown) on an upper surface 178A of the contact plate 178for engaging corresponding contacts on the wireless transmitter/powerpack unit 176. The wireless transmitter/power pack unit 176 can beremoved from the docking area 175 for recharging a power pack or batterycontained therein. It is also contemplated that the wirelesstransmitter/power pack unit 176 may be non-removable, i.e., integralwith or sealed within the base 172 and upper housing 174. In this latterembodiment, the wireless transmitter/power pack unit 176 includes areceptacle (not shown) for receiving an AC adapter for charging thepower or battery pack.

The rigid base 172 is provided with a first slot 172A for receiving aholding strap 190, which will be discussed below, see FIGS. 10D and 10E.The rigid base 172 also has a finger-engaging extension 172B extendingdownward from a lower surface 172C of the base 172 so as to define aportion of a first finger receiving area 200 and a second fingerreceiving area 202, see FIG. 10F.

The finger-mounted remote control device 170 further comprises controlstructure 180. The control structure 180 comprises a backing plate 182having a recess 282A and a two-state switch 183 received in the recess282A. Conductors or wires (not shown) extend from the switch 183 to alower surface 178B of the contact plate 178 such that signals generatedby the switch 183 when activated, as will be discussed below, aredelivered via the conductors to the contact plate 178 and from thecontact plate 178 to the transmitter/power pack unit 176. The backingplate 182 further comprises four bores 182A and a curved lower surface182C, which defines a portion of the first finger receiving area 200,see FIGS. 10B, 10E and 10F.

The control structure 180 further comprises a button and support plateassembly 184. The support plate assembly 184 may be formed from a rigidpolymeric material and comprises four bores 184A that align with thefour bores 182A in the backing plate 182. A “Go” button 184B, defined bya flexible polymeric member, is integral with or coupled to asurrounding portion of the support plate 184. The button 184B covers theswitch 183. A lower portion 185 of the support plate assembly 184 isprovided with a second slot 185A for receiving the holding strap 190. Acurved lower surface 185B of the support plate lower portion 185 definesa portion of the first finger receiving area 200, see FIGS. 10E and 10F.An outer cover plate 186 having an opening 186A is fitted over thebutton and support plate assembly 184. Four screws 186B extend throughthe bores 182A in the backing plate 182 and the bores 184A in thesupport plate 184 and are received in threaded openings (not shown) inthe outer cover plate 186. The cover plate 186 further comprises firstand second laterally extending ears 286 provided with bores 286A throughwhich two of the bolts 273A, noted above, pass. Hence, the bolts 273couple the control structure 180 to the base and upper housing 172 and174.

As illustrated in FIGS. 9A and 9B, the remote control device 170 isadapted to be fitted over index and middle fingers F_(I) and F_(M) of anoperator, wherein the index finger is received in the first fingerreceiving area 200 and the middle finger is received in the secondfinger receiving area 202. Both right and left hand versions of thecontrol device 170 may be created.

The finger-mounted remote control device 170 is compact. As is apparentfrom FIGS. 9A and 9B, substantially the entirety of the remote controldevice 170 is mounted and positioned directly over the index and middlefingers F_(I) and F_(M) of an operator. Hence, approximately 60% or moreof the wireless transmitter/power pack unit 176 is positioned directlyover the operator's fingers F while a small remaining portion extendsover the hand portion HP extending away from the base F_(B) of thefingers F, see FIG. 9.

The control device 170 is releasably held on the operator's index andmiddle fingers via the holding strap 190. A first end 190A of theholding strap 190 is threaded through the first slot 172A in the rigidbase 172 and the second slot 185A in the lower portion 185 of thesupport plate 184. A second end 190B of the strap 190 is enlarged so asnot to pass through the first slot 172A, see FIG. 10E. A first portion190C of the strap 190, extending generally from the strap second end190B to the second slot 185A, extends across the operator's index andmiddle fingers, see FIG. 9. A second portion 190D of the strap 190,extending generally from the second slot 185A to the strap first end190A, is folded back onto the strap first portion 190C and releasablyattached to the strap first portion 190C such as by hook and loopfasteners, i.e., Velcro (trademark) or like fastening structure. It isnoted that other types of mounting straps 190 may be used, such as, forexample expandable/flexible straps, rigid or flexible rings, etc.

It is contemplated that the finger-mounted remote control device 170 maybe worn by an operator over a glove. In the illustrated embodiment, thefinger-mounted remote control device 170 is durable and long lastingsince the rigid base 172, the upper housing 174 and the outer coverplate 186 are preferably formed from a durable and rigid polymericmaterial, such as acrylonitrile butadiene styrene (ABS), polycarbonateor nylon. The rigid base 172, the upper housing 174 and the outer coverplate 186 define a durable, generally non-flexible and rigid mountingstructure 270.

An operator can easily manually actuate the go button 184B via histhumb, thereby actuating the switch 183, to cause the wirelesstransmitter/power pack unit 176 to wirelessly transmit at least a firsttype signal designating a travel request or command to the vehicle. Itis contemplated that the travel request may result in the vehicle 10traveling by a predetermined distance or for a predetermined amount oftime. It is also contemplated that a brief actuation of the go button184B may result in the vehicle 10 traveling for a predetermined distanceor for a predetermined amount of time, while a prolonged actuation ofthe go button 184B may result in continuous movement of the vehicle 10until the go button 184B is released.

It is noted that the finger-mounted remote control device 170 describedherein is an exemplary configuration and may be structurally modifiedwithout departing from the spirit and scope of the invention. Forexample, one or more components of the finger-mounted remote controldevice 170 may be combined in an integral component, or components maybe substituted for alternate components that effect a similar/identicalpurpose. As a few examples, the support plate assembly 184 and the outercover plate 186 may be combined into an integral piece, which integralpiece may be coupled to the backing plate 182 by structure other thanscrews 186B.

The truck 10 also comprises one or more obstacle sensors 76, which areprovided about the vehicle, e.g., towards the first end section of thepower unit 14 and/or to the sides of the power unit 14. The obstaclesensors 76 include at least one contactless obstacle sensor on thevehicle, and are operable to define at least one detection zone (alsoreferred to herein as scan zones), each detection zone defining an areaat least partially in front of a forward traveling direction of thevehicle when the vehicle is traveling under remote control in responseto a travel request as will be described in greater detail herein. Theobstacle sensors 76 may comprise any suitable proximity detectiontechnology, such as an ultrasonic sensors, optical recognition devices,infrared sensors, laser sensors, etc., which are capable of detectingthe presence of objects/obstacles within the predefined detection zonesof the power unit 14.

In practice, the truck 10 may be implemented in other formats, stylesand features, such as an end control pallet truck that includes asteering tiller arm that is coupled to a tiller handle for steering thetruck. In this regard, the truck 10 may have similar or alternativecontrol arrangements to that shown in FIG. 1. Still further, the truck10, remote control system and/or components thereof, may comprise anyadditional and/or alternative features, such as set out in U.S.Provisional Patent Application Ser. No. 60/825,688, filed Sep. 14, 2006entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING A MATERIALSHANDLING VEHICLE;” U.S. patent application Ser. No. 11/855,310, filedSep. 14, 2007 entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING AMATERIALS HANDLING VEHICLE;” U.S. patent application Ser. No.11/855,324, filed Sep. 14, 2007 entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE;” U.S. ProvisionalPatent Application Ser. No. 61/119,952, filed Dec. 4, 2008 entitled“MULTIPLE ZONE SENSING FOR REMOTELY CONTROLLED MATERIALS HANDLINGVEHICLES;” U.S. Provisional Patent Application Ser. No. 61/234,866,filed Aug. 18, 2009, entitled “STEER CORRECTION FOR A REMOTELY OPERATEDMATERIALS HANDLING VEHICLE;” and/or U.S. Pat. No. 7,017,689, issued Mar.28, 2006, entitled “ELECTRICAL STEERING ASSIST FOR MATERIAL HANDLINGVEHICLE,” the entire disclosures of which are each hereby incorporatedby reference herein.

Control System for Remote Control of a Low Level Order Picking Truck

Referring to FIG. 2, a block diagram 100 illustrates a controlarrangement for integrating remote control commands with the truck 10.The antenna 66 is coupled to a receiver 102 for receiving commandsissued by the remote control device 70, 170. The receiver 102 passes thereceived control signals to a controller 103, which implements theappropriate response to the received commands. The response may compriseone or more actions, or inaction, depending upon the logic that is beingimplemented. Positive actions may comprise controlling, adjusting orotherwise affecting one or more components of the truck 10. Thecontroller 103 may also receive information from other inputs 104, e.g.,from sources such as the presence sensors 58, the obstacle sensors 76,switches, load sensors, encoders and other devices/features available tothe truck 10 to determine appropriate action in response to the receivedcommands from the remote control device 70, 170. The sensors 58, 76,etc. may be coupled to the controller 103 via the inputs 104 or via asuitable truck network, such as a control area network (CAN) bus 110.

In an exemplary arrangement, the remote control device 70, 170 isoperative to wirelessly transmit a control signal that represents afirst type signal such as a travel command to the receiver 102 on thetruck 10. The travel command is also referred to herein as a “travelsignal”, “travel request” or “go signal”. The travel request is used toinitiate a request to the truck 10 to travel by a predetermined amount,e.g., to cause the truck 10 to advance or jog in a first direction by alimited travel distance. The first direction may be defined, forexample, by movement of the truck 10 in a power unit 14 first, i.e.,forks 16 to the back, direction. However, other directions of travel mayalternatively be defined. Moreover, the truck 10 may be controlled totravel in a generally straight direction or along a previouslydetermined heading. Correspondingly, the limited travel distance may bespecified by an approximate travel distance, travel time or othermeasure.

Thus, a first type signal received by the receiver 102 is communicatedto the controller 103. If the controller 103 determines that the travelsignal is a valid travel signal and that the current vehicle conditionsare appropriate (explained in greater detail below), the controller 103sends a signal to the appropriate control configuration of theparticular truck 10 to advance and then stop the truck 10. As will bedescribed in greater detail herein, stopping the truck 10 may beimplemented, for example, by either allowing the truck 10 to coast to astop or by applying a brake to stop the truck.

As an example, the controller 103 may be communicably coupled to atraction control system, illustrated as a traction motor controller 106of the truck 10. The traction motor controller 106 is coupled to atraction motor 107 that drives at least one steered wheel 108 of thetruck 10. The controller 103 may communicate with the traction motorcontroller 106 so as to accelerate, decelerate, adjust and/or otherwiselimit the speed of the truck 10 in response to receiving a travelrequest from the remote control device 70, 170. The controller 103 mayalso be communicably coupled to a steer controller 112, which is coupledto a steer motor 114 that steers at least one steered wheel 108 of thetruck 10. In this regard, the truck may be controlled by the controller103 to travel an intended path or maintain an intended heading inresponse to receiving a travel request from the remote control device70, 170.

As yet another illustrative example, the controller 103 may becommunicably coupled to a brake controller 116 that controls truckbrakes 117 to decelerate, stop or otherwise control the speed of thetruck in response to receiving a travel request from the remote controldevice 70, 170. Still further, the controller 103 may be communicablycoupled to other vehicle features, such as main contactors 118, and/orother outputs 119 associated with the truck 10, where applicable, toimplement desired actions in response to implementing remote travelfunctionality.

According to various aspects of the present invention, the controller103 may communicate with the receiver 102 and with the tractioncontroller 106 to operate the vehicle under remote control in responseto receiving travel commands from the associated remote control device70, 170. Moreover, the controller 103 may be configured to perform afirst action if the vehicle is traveling under remote control inresponse to a travel request and an obstacle is detected in a first oneof the detection zones. The controller 103 may be further configured toperform a second action different from the first action if the vehicleis traveling under remote control in response to a travel request and anobstacle is detected in a second one of the detection zones. In thisregard, when a travel signal is received by the controller 103 from theremote control device 70, 170, any number of factors may be consideredby the controller 103 to determine whether the travel signal should beacted upon and what action(s) should be taken, if any. The particularvehicle features, the state/condition of one or more vehicle features,vehicle environment, etc., may influence the manner in which controller103 responds to travel requests from the remote control device 70, 170.

The controller 103 may also refuse to acknowledge the travel signaldepending upon vehicle condition(s), e.g., that relate to environmentalor/operational factor(s). For example, the controller 103 may disregardan otherwise valid travel request based upon information obtained fromone or more of the sensors 58, 76. For example, according to variousaspects of the present invention, the controller 103 may optionallyconsider factors such as whether an operator is on the truck 10 whendetermining whether to respond to a travel command from the remotecontrol device 70, 170. For example, as noted above, the truck 10 maycomprise at least one presence sensor 58 for detecting whether anoperator is positioned on the vehicle. In this regard, the controller103 may be further configured to respond to a travel request to operatethe vehicle under remote control when the presence sensor(s) 58designate that no operator is on the vehicle.

Any other number of reasonable conditions may also/alternatively beimplemented by the controller 103 to interpret and take action inresponse to received signals. Other exemplary factors are set out ingreater detail in U.S. Provisional Patent Application Ser. No.60/825,688, filed Sep. 14, 2006 entitled “SYSTEMS AND METHODS OFREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S. patentapplication Ser. No. 11/855,310, filed Sep. 14, 2007 entitled “SYSTEMSAND METHODS OF REMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE,” U.S.patent application Ser. No. 11/855,324, filed Sep. 14, 2007 entitled“SYSTEMS AND METHODS OF REMOTELY CONTROLLING A MATERIALS HANDLINGVEHICLE,” U.S. Provisional Patent Application Ser. No. 61/119,952, filedDec. 4, 2008 entitled “MULTIPLE ZONE SENSING FOR REMOTELY CONTROLLEDMATERIALS HANDLING VEHICLES,” and U.S. Provisional Patent ApplicationSer. No. 61/234,866, filed Aug. 18, 2009, entitled “STEER CORRECTION FORA REMOTELY OPERATED MATERIALS HANDLING VEHICLE,” the disclosures ofwhich are each already incorporated by reference herein.

Upon acknowledgement of a travel request, the controller 103 interactswith the traction motor controller 106, e.g., directly, indirectly, viathe CAN bus 110, etc., to advance the truck 10. Depending upon theparticular implementation, the controller 103 may interact with thetraction motor controller 106 to advance the truck 10 by a predetermineddistance. Alternatively, the controller 103 may interact with thetraction motor controller 106 to advance the truck 10 for a period oftime in response to the detection and maintained actuation of a travelcontrol on the remote 70. Further alternatively, the truck 10 may beconfigured to jog for as long as a travel control signal is received.Still further alternatively, the controller 103 may be configured to“time out” and stop the travel of the truck 10 based upon apredetermined event, such as exceeding a predetermined time period ortravel distance regardless of the detection of maintained actuation of acorresponding control on the remote control device 70, 170.

The remote control device 70, 170 may also be operative to transmit asecond type signal, such as a “stop signal”, designating that the truck10 should brake and/or otherwise come to rest. The second type signalmay also be implied, e.g., after implementing a “travel” command, e.g.,after the truck 10 has traveled a predetermined distance, traveled for apredetermined time, etc., under remote control in response to the travelcommand. If the controller 103 determines that the signal is a stopsignal, the controller 103 sends a signal to the traction controller106, the brake controller 116 and/or other truck component to bring thetruck 10 to a rest. As an alternative to a stop signal, the second typesignal may comprise a “coast signal”, designating that the truck 10should coast, eventually slowing to rest or a “controlled decelerationsignal.”

The time that it takes to bring the truck 10 to a complete rest mayvary, depending for example, upon the intended application, theenvironmental conditions, the capabilities of the particular truck 10,the load on the truck 10 and other similar factors. For example, aftercompleting an appropriate jog movement, it may be desirable to allow thetruck 10 to “coast” some distance before coming to rest so that thetruck 10 stops slowly. This may be achieved by utilizing regenerativebraking to slow the truck 10 to a stop. Alternatively, a brakingoperation may be applied after a predetermined delay time to allow apredetermined range of additional travel to the truck 10 after theinitiation of the stop operation. It may also be desirable to bring thetruck 10 to a relatively quicker stop, e.g., if an object is detected inthe travel path of the truck 10 or if an immediate stop is desired aftera successful jog operation. For example, the controller may applypredetermined torque to the braking operation. Under such conditions,the controller 103 may instruct the brake controller 116 to apply thebrakes 117 to stop the truck 10.

Detection Zones of a Materials Handling Vehicle

Referring to FIG. 3, according to various aspects of the presentinvention, one or more obstacle sensors 76 are configured so as tocollectively enable detection of objects/obstacles within multiple“detection zones”. In this regard, the controller 103 may be configuredto alter one or more operational parameters of the truck 10 in responseto detection of an obstacle in one or more of the detection zones as setout in greater detail herein. The control of the vehicle utilizingdetection zones may be implemented when an operator is riding/drivingthe vehicle. The control of the vehicle utilizing detection zones mayalso be integrated with supplemental remote control as set out anddescribed more fully herein. When an operator is riding the vehicle theoperator may have the option of disabling one or more of the detectionzones and/or one or more of the responses of the controller when thedetectors detect an object, as described below.

Although six obstacle sensors 76 are shown for purposes of clarity ofdiscussion herein, any number of obstacle sensors 76 may be utilized.The number of obstacle sensors 76 will likely vary, depending upon thetechnology utilized to implement the sensor, the size and/or range ofthe detection zones, the number of detection zones, and/or otherfactors.

In the illustrative example, a first detection zone 78A is locatedproximate to the power unit 14 of the truck 10. A second detection zone78B is defined adjacent to the first detection zone 78A and appears togenerally circumscribe the first detection zone 78A. A third area isalso conceptually defined as all area outside the first and seconddetection zones 78A, 78B. Although the second detection zone 78B isillustrated as substantially circumscribing the first detection zone78A, any other practical arrangement that defines the first and seconddetection zones 78A, 78B may be realized. For example, all or certainportions of the detection zones 78A, 78B may intersect, overlap or bemutually exclusive. Moreover, the particular shape of the detectionzones 78A, 78B can vary. Still further, any number of detection zonesmay be defined, further examples of which are described in greaterdetail herein.

Still further, the detection zones need not surround the entire truck10. Rather, the shape of the detection zones may be dependent upon theparticular implementation as set out in greater detail herein. Forexample, if the detection zones 78A, 78B are to be used for speedcontrol while the truck 10 is moving without an operator riding thereon,under remote travel control in a power unit first (forks to the rear)orientation, then the detection zones 78A, 78B may be oriented forwardof the direction of travel of the truck 10. However, the detection zonescan also cover other areas, e.g., adjacent to the sides of the truck 10.

According to various aspects of the present invention, the firstdetection zone 78A may further designate a “stop zone”. Correspondingly,the second detection zone 78B may further designate a “first speedzone”. Under this arrangement, if an object, e.g., some form of obstacleis detected within the first detection zone 78A, and the materialshandling vehicle 10 is traveling under remote control in response to atravel request, then the controller 103 may be configured to implementan action such as a “stop action” to bring the truck 10 to a stop. Inthis regard, travel of the truck 10 may continue once the obstacle isclear, or a second, subsequent travel request from the remote controldevice 70, 170 may be required to restart travel of the truck 10.

If a travel request is received from the remote control device 70, 170while the truck is at rest and an object is detected within the firstdetection zone 78A, then the controller 103 may refuse the travelrequest and keep the truck at rest until the obstacle is cleared out ofthe stop zone.

If an object/obstacle is detected within the second detection zone 78B,and the materials handling vehicle 10 is traveling under remote controlin response to a travel request, then the controller 103 may beconfigured to implement a different action. For example, the controller103 may implement a first speed reduction action to reduce the speed ofthe vehicle to a first predetermined speed, such as where the vehicle istraveling at a speed greater than the first predetermined speed.

Thus, assume the truck 10 is traveling in response to implementing atravel request from the remote control device at a speed V2 asestablished by a set of operating conditions where the obstacle sensors76 do not detect an obstacle in any detection zone. If the truck isinitially at rest, the truck may be accelerated up to speed V2. Thedetection of an obstacle within the second detection zone 78B (but notthe first detection zone 78A) may cause the truck 10, e.g., via thecontroller 103 to alter at least one operational parameter, e.g., toslow down the truck 10 to a first predetermined speed V1, which isslower than the speed V2. That is, V1<V2. Once the obstacle is clearedfrom the second detection zone 78B, the truck 10 may resume its speedV2, or the truck 10 may maintain its speed V1 until the truck stops andthe remote control device 70, 170 initiates another travel request.Still further, if the detected object is subsequently detected withinthe first detection zone 78A, the truck 10 will be stopped as describedmore fully herein.

Assume as an illustrative example, that the truck 10 is configured totravel at a speed of approximately 2.5 miles per hour (mph) (4Kilometers per hour (Km/h)) if the truck 10 is traveling without anoperator onboard and is under remote control in response to a travelrequest from a corresponding remote control 70, so long as no object isdetected in a defined detection zone. If an obstacle is detected in thesecond detection zone 78B, then the controller 103 may adjust the speedof the truck 10 to a speed of approximately 1.5 mph (2.4 Km/h) or someother speed less than 2.5 miles per hour (mph) (4 Kilometers per hour(Km/h)). If an obstacle is detected in the first detection zone 78A,then the controller 103 stops the truck 10.

The above example assumes that the truck 10 is traveling under remotecontrol. In this regard, the obstacle sensors 76 can be used to adjustthe operating conditions of the unoccupied truck 10. However, theobstacle sensors 76 and corresponding controller logic may also beoperative when the truck 10 is being driven by an operator, e.g., ridingon the platform or other suitable location of the truck 10. Thus,according to various aspects of the present invention, the controller103 may stop the vehicle or refuse to allow the vehicle to move if anobject is detected within the stop zone 78A regardless of whether thetruck is being driven by an operator or operating under remote control.Correspondingly, depending upon the specific implementation, its speedcontrol capability of the second detection zone 78B may be implementedregardless of whether the vehicle is operating under remote control, orwhether an operator is riding on the vehicle while driving it.

However, according to various aspects of the present invention, theremay be situations where it is desirable to disable one or more of thedetection zones when the truck 10 is being driven by an operator. Forexample, it may be desirable to override/disable the obstacle sensors76/controller logic while the operator is driving the truck 10regardless of external conditions. As a further example, it may bedesirable to override/disable the obstacle sensors 76/controller logicwhile the operator is driving the truck 10 to allow the operator tonavigate the truck 10 in tight quarters, e.g., to navigate tight spaces,travel around corners, etc., that might otherwise activate one or moreof the detection zones. As such, the activation of the controller logicto utilize the detection of objects in the detection zones to helpcontrol the vehicle while the vehicle is occupied by an operator,according to various aspects of the present invention, may be manuallycontrolled, programably controlled or otherwise selectively controlled.

According to other aspects of the present invention, it may be desirableto disable one or more of the detection zones when an operator iswalking alongside the truck 10 and controlling operation of the truck 10with a supplemental control, such as a jog switch/button, e.g., locatedon a side portion of the truck 10. Such a jog switch may be used to moveor jog the truck 10 in a forward direction at a predetermined andpreferably low speed, as will be apparent to those skilled in the art.For example, it may be desirable to override/disable the obstaclesensors 76/controller logic while the operator is actuating the jogswitch regardless of external conditions. As a further example, it maybe desirable to override/disable the obstacle sensors 76/controllerlogic while the operator is actuating the jog switch to allow theoperator to navigate the truck 10 in tight quarters, e.g., to navigatetight spaces, travel around corners, etc., that might otherwise activateone or more of the detection zones. As yet a further example, upon theoperator releasing the jog switch, the truck 10 may coast to a stop.Upon the releasing of the jog switch and the truck 10 coasting, one ormore of the disabled detection zones may be enabled, i.e., by enablingone or more of the obstacle sensors 76/controller logic.

Referring to FIG. 4, according to further aspects of the presentinvention, one or more of the obstacle sensors 76 may be implemented byultrasonic technology, laser technology, or other suitable contactlesstechnology capable of a distance measurement and/or positiondetermination. Thus, the distance to an object can be measured, and/or adetermination may be made so as to ascertain whether the detected objectis within a detection zone 78A, 78B, e.g., by virtue of the distance ofthe object from the truck 10. As an example, an obstacle sensor 76 maybe implemented by an ultrasonic sensor or transducer that provides a“ping” signal, such as a high frequency signal generated by a piezoelement. The ultrasonic sensor 76 then rests and listens for a response.In this regard, time of flight information may be determined andutilized to define each zone. Thus, a controller, e.g., the controller103 or a controller specifically associated with the obstacle sensors 76may utilize software that looks at time of flight information todetermine whether an object is within a detection zone.

According to further aspects of the present invention, multiple obstaclesensors 76 can work together to obtain object sensing. For example, afirst ultrasonic sensor may send out a ping signal. The first ultrasonicsensor and one or more additional ultrasonic sensors may then listen fora response. In this way, the controller may use diversity in identifyingthe existence of an object within one or more of the detection zones.

With reference to FIG. 5, an implementation of multiple speed zonecontrol is illustrated according to yet further aspects of the presentinvention. As illustrated, three detection zones are provided. If anobject such as an obstacle is detected in the first detection zone 78Aand the truck 10 is moving under remote control, then a first action maybe performed, e.g., the truck 10 may be brought to a stop as describedmore fully herein. If an object such as an obstacle is detected in thesecond detection zone 78B and the truck 10 is moving under remotecontrol, then a second action may be performed, e.g., the vehicle speedmay be limited, reduced, etc. Thus, the second detection zone 78B mayfurther designate a first speed zone. For example, the speed of thetruck 10 may be reduced and/or limited to a first relatively slow speed,e.g., approximately 1.5 mph (2.4 Km/h).

If an object such as an obstacle is detected in the third detection zone78C and the truck 10 is moving under remote control, then a third actionmay be performed, e.g., the truck 10 may be reduced in speed orotherwise limited to a second speed, e.g., approximately 2.5 mph (4Km/h). Thus, the third detection zone may further designate a secondspeed zone. If no obstacles are detected in the first, second and thirddetection zones 78A, 78B, 78C, then the vehicle may be remotelycontrolled to travel, e.g., in response to a remote travel request, at arate that is greater than the rate of speed when an obstacle is in thethird detection zone, e.g., a speed of approximately 4 mph (6.2 Km/h).

As FIG. 5 further illustrates, the detection zones may be defined bydifferent patterns relative to the truck 10. Also, in FIG. 5, a seventhobstacle sensor 76 is illustrated for purposes of illustration. By wayof illustration, the seventh obstacle sensor 76 may be approximatelycentered, such as on the bumper or other suitable location on the truck10. On an exemplary truck 10, the third zone 78C may extendapproximately 6.5 feet (2 meters) forward of the power unit 14 of thetruck 10.

According to various aspects of the present invention, any number ofdetection zones of any shape may be implemented. For example, dependingupon desired truck performance, many small zones may be defined atvarious coordinates relative to the truck 10. Similarly, a few largedetection zones may be defined base upon desired truck performance. Asan illustrative example, a database, equation, function or other meansof data comparison, such as a look-up table may be set up in the memoryof the controller. If travel speed while operating under remote travelcontrol is an operational parameter of interest, then the table mayassociate travel speed with the detection zones defined by distance,range, position coordinates or some other measure. If the truck 10 istraveling under remote control and an obstacle sensor detects an object,then the distance to that detected object may be used as a “key” to lookup a corresponding travel speed in the table. The travel speed retrievedfrom the table can be utilized by the controller 103 to adjust the truck10, e.g., to slow it down, etc.

Depending upon factors such as the desired speed of the truck whenoperating under remote control and the required stopping distance, theanticipated load to be transported by the truck 10, whether a certainamount of coast is required for load stability, vehicle reaction time,etc., the areas of each detection zone may be chosen. Moreover, factorssuch as the range of each desired detection zone etc. may be consideredto determine the number of obstacle sensors 76 required. In this regard,such information may be static, or dynamic, e.g., based upon operatorexperience, vehicle load, nature of the load, environmental conditions,etc.

It is also contemplated that the controller 103 may generate a warningsignal or alarm if an object or a person is detected in a detectionzone.

As an illustrative example, in a configuration with multiple detectionzones, e.g., three detection zones, as many as seven or more objectdetectors, e.g., ultrasonic sensors and/or laser sensors may be requiredto provide a range of coverage desired by a corresponding application.In this regard, the detector(s) may be able to look ahead of thedirection of travel of the vehicle by a sufficient distance to allow theappropriate response, e.g., to slow down. In this regard, at least onesensor may be capable of looking several meters forward in the directionof travel of the truck 10.

According to various aspects of the present invention, the multipledetection speed zones allows a relatively greater maximum forward travelspeed while operating under remote control that prevents unnecessarilyearly vehicle stops by providing one or more intermediate zones wherethe vehicle slows down before deciding to come to a complete stop.

According to further aspects of the present invention, the utilizationof multiple detection zones allows a system that rewards thecorresponding operator for better alignment of the truck 10 during pickoperations. For example, an operator may position the truck 10 so as tonot be aligned with a warehouse aisle. As such, as the vehicle is joggedforward, the second detection zone 78B may initially detect an obstaclesuch as a pick bin or warehouse rack. In response to detecting the rack,the vehicle will slow down. If the rack is sensed in the first detectionzone 78A, then the vehicle will come to rest, even if the truck 10 hasnot jogged its entire programmed jog distance. Similar un-necessaryslow-downs or stops may also occur in congested and/or messy aisles.

According to various aspects of the present invention, the truck 10 mayshape speed and braking operation parameters based upon the informationobtained from the obstacle sensors 76. Moreover, the logic implementedby the truck 10 in response to the detection zones may be changed orvaried depending upon a desired application. As a few illustrativeexamples, the boundaries of each zone in a multiple zone configurationmay be programably (and/or reprogramably) entered in the controller,e.g., flash programmed. In view of the defined zones, one or moreoperational parameters may be associated with each zone. The establishedoperational parameters may define a condition, e.g., maximum allowabletravel speed, an action, e.g., brake, coast or otherwise come to acontrolled stop, etc. The action may also be an avoidance action. Forexample, an action may comprise adjusting a steer angle or heading ofthe truck 10.

In accordance with a further embodiment of the present invention, one ormore obstacle sensors, such as the obstacle sensors 76A, 76B shown inFIGS. 6 and 8, may be employed to sense or detect objects within first,second and third detection zones in front of the materials handlingvehicle 10 when the vehicle 10 is traveling under remote control inresponse to a travel request command or signal and generate anobject-detected and distance signal to the controller 103 in response tosensing/detecting an object in front of the vehicle 10. A further input104 into the controller 103 may be a weight signal generated by a loadsensor LS, see FIG. 8, which senses the combined weight of the forks 16and any load on the forks 16. The load sensor LS is shown schematicallyin FIGS. 7 and 8 near the forks 16, but may be incorporated into ahydraulic system for effecting lift of the forks 16. By subtracting theweight of the forks 16 (a known constant value) from the combined weightdefined by the weight signal, the controller 103 determines the weightof the load on the forks. Using sensed load weight and whether an objecthas been detected in one of the first, second and third detection zonesas inputs into a lookup table or appropriate equations, the controller103 generates an appropriate vehicle stop or maximum allowable speedsignal.

Values defining the vehicle stop and maximum allowable speed signals maybe experimentally determined and stored in a look-up table, such as theone illustrated in FIG. 11. In the illustrated embodiment, thecontroller 103 determines the weight of a load on the forks 16 andwhether an obstacle has been detected in one of the first, second andthird detection zones and, using the lookup table in FIG. 11, effects astop command or defines a maximum allowable speed for the vehicle 10 andgenerates a corresponding maximum allowable speed signal for the vehicle10.

With reference to the example lookup table in FIG. 11, if no load is onthe forks 16 and no object is being detected by the obstacle sensors76A, 76B in any one of the first, second and third detection zones, thecontroller 103 allows the vehicle to be operated at any speed up to andincluding a maximum speed of 4.5 MPH. As is apparent from FIG. 11, if noobject is being detected in any one of the first, second and thirddetection zones, the maximum permitted speed decreases as the load onthe vehicle increases. For example, for a load weight of 8000 pounds,the maximum allowable speed of the vehicle is 2.5 MPH. It is noted that,in some locations the maximum allowable speed of the vehicle 10, ifunoccupied by a rider, may be set at a predetermined upper limit, e.g.,3.5 MPH. Hence, the maximum speed of the vehicle, if unoccupied by arider, may be set, e.g., by the controller 103, at this maximumallowable speed.

For any load weight on the forks 16, if an object is detected in thefirst detection zone, the controller 103 generates a “stop signal,”designating that the vehicle 10 brake. For any given load weight, themaximum allowable speed of the vehicle is less if an object is detectedin the second or the third detection zone as compared to a state whereno object is being detected. Also for any given load weight, the maximumallowable speed of the vehicle is less if an object is detected in thesecond detection zone as compared to when an object is detected in thethird detection zone. The maximum allowable vehicle speeds for thesecond and third detection zones are defined for each load weight sothat the vehicle's speed can be reduced in a controlled manner as thevehicle continues to move towards the object so that the vehicle caneventually be safely brought to a stop prior to the truck reaching thepoint where the object is located. These speeds are experimentallydetermined and can vary based on vehicle type, size and its brakingcapabilities.

For example, if the load weight on the vehicle equals 1500 pounds, andan object is sensed in the first detection zone, which first zone isnearest to the vehicle power unit 14, then a stop signal is generated bythe controller 103 to effect stopping of the vehicle 10, see FIG. 11. Ifthe load weight on the vehicle remains equal to 1500 pounds, and if asensed object is located at a distance from the vehicle 10 within thesecond detection zone, spaced further away from the power unit 14 thanthe first detection zone, then the maximum allowable vehicle speed isequal to 2.0 MPH, see FIG. 11. Hence, if the vehicle 10 traveling at aspeed greater than 2.0 MPH when the object is detected, the controller103 effects a speed reduction so that the vehicle speed is reduced to2.0 MPH. If the load weight on the vehicle remains equal to 1500 pounds,and if a sensed object is located at a distance within the thirddetection zone, spaced further away from the power unit 14 than thefirst and second detection zones, then the maximum allowable vehiclespeed is equal to 3.0 MPH. Hence, if the vehicle 10 traveling at a speedgreater than 3.0 MPH when the object is detected, the controller 103effects a speed reduction so that the vehicle speed is reduced to 3.0MPH.

The obstacle sensors may comprise ultrasonic transducers. Ultrasonictransducers are known to experience a phenomena known as transducer“ring down.” Essentially “ring down” is the tendency of a transducer tocontinue to vibrate and transmit ultrasonic signals after the controlsignal that is used for initiating a transmitted signal has ceased. This“ring down” signal decreases in magnitude rather rapidly, but during thetime that it is decreasing to a level below a threshold detection level,detection structure forming part of each obstacle sensor will respond tosuch “ring down” signals if the signals are above a reference level andthus can indicate that a “ring down” signal is a reflected or returnsignal when in fact it is not. A common technique to avoid this problemis to blank out all return signals generated by the obstacle sensors fora preselected period of time after initiation of a transmission. Thepreselected time is determined based on various factors including thetype of transducer that is used, but during this preselected time novalid returns can be sensed. If the obstacle sensors are positioned neara front 10A of the vehicle 10, see obstacle sensors 76A in FIG. 7, andif the blanking technique is used, this results in a “dead” or“non-detect” zone DZ existing immediately in front of the vehicle 10.Hence, if an object O is very near the front of the vehicle, e.g., 10 mmor less, and the obstacle sensors 76A are positioned at the front of thevehicle, see FIG. 7, then the object O may not be detected.

In the embodiment illustrated in FIGS. 6 and 8, first and secondobstacle sensors 76A and 76B, respectively, are spaced apart from oneanother along a longitudinal axis L_(A) of the vehicle 10, see FIG. 8.The first obstacle sensors 76A are positioned at the front 10A of thevehicle 10 and are capable of sensing objects in the second and thirddetection zones as well as a first portion of the first detection zone,which first detection zone first portion is a predefined distance aheadof the front 10A of the vehicle 10, e.g., a distance 10 mm or greater infront of the vehicle front 10A. So as to ensure that objects O locatedin the non-detect zone DZ, i.e., an area not sensed by the firstobstacle sensors 76A, the second obstacle sensors 76B are positioned onthe vehicle 10 a spaced distance behind the first sensors 76A, i.e., ina direction away from the vehicle front 10A, see FIG. 8. Hence, thesecond sensors 76B function to sense objects in a first detection zoneremaining second portion Z_(II) just in front of the vehicle front 10Aand corresponding to the dead zone DZ in FIG. 7.

Algorithm

According to various aspects of the present invention, a steercorrection algorithm is implemented, e.g., by the controller 103.Referring to FIG. 12, a steer correction algorithm comprises determiningwhether a steer bumper zone warning is detected at 152. A steer bumpersignal warning at 152 may comprise, for example, detecting the presenceof an object within first and/or second steer bumper zones 132A, 132Bwith a laser sensor 2000, such as a model number LMS 100 or LMS 111laser sensor manufactured by Sick AG located in Waldkirch, Germany. Thelaser sensor 2000 may be mounted to the power unit 14, see FIG. 13. Thefirst steer bumper zone 132A may also be designated as a left steerbumper zone and the second steer bumper zone 132B may also be designatedas a right steer bumper zone, see FIG. 13. If a steer bumper zonewarning is received, a determination is made at 154 whether the steerbumper zone warning indicates that an object is detected to the left orto the right of the truck 10, e.g., whether the detected object is inthe first steer bumper zone 132A or the second steer bumper zone 132B.For example, the laser sensor 2000 may generate two outputs, a firstoutput signal designating whether an object is detected in the first(left) steer bumper zone 132A, and a second signal designating whetheran object is detected in the second (right) steer bumper zone 132B.Alternatively, the controller 103 may receive raw laser sensor data andprocess/distinguish the first and second steer bumper zones 132A, 132Busing a predetermined mapping.

For example, referring additionally to FIG. 13, the laser sensor 2000may sweep a laser beam in an area in front of truck 10. In this regard,multiple laser sensors may be utilized, or one or more laser beams maybe swept, e.g., to raster scan one or more areas forward of the truck10. If an object is present in an area where the laser beams are swept,the object reflects the beam back to the laser sensor 2000, which iscapable of generating object location data from which the location ofthe sensed object can be determined either by the sensor 2000 or thecontroller 103, as is known in the laser sensor art. In this regard, thelaser sensor 2000 may independently define and scan the left and rightsteer bumper zones, or the controller 103 may derive the left and/orright steer bumper zones based upon the raster scan of the laser(s).Still further, alternate scanning patterns may be utilized, so long asthe controller 103 can determine whether a detected obstacle is to theleft or to the right of the truck 10.

As a few additional examples, although a laser sensor 2000 isillustrated for purposes of discussion herein, other sensingtechnologies may be utilized, examples of which may include ultrasonicsensors, infrared sensors, etc. For example, ultrasonic sensors, e.g.,located to the sides of the truck 10, may define the left and rightsteer bumper zones 132A, 132B. Selection of the type(s) of sensors usedon the truck 10 may depend upon the particular operating conditions ofthe truck 10.

Additionally, the laser sensor 2000 or one or more additional sensorsmay be used to define other detection zones, e.g., for stopping, speedlimiting, etc. The laser sensor 2000 (or one or more additional sensors)may define a “stop zone”, and/or a “slow down zone” as described indetail herein. For example, if a single stop zone is defined and anobject is detected in the stop zone, which may extend, for example,about 1.2 meters in front of a forward traveling direction of the truck10, the controller 103 may cause the truck 10 to stop, as set out indetail herein. Additionally or alternatively, if an object is detectedin a slow down zone, the controller 103 may cause the truck 10 to slowdown. It is noted that, according to this embodiment, it may bepreferable to define a stop zone while not defining a slow down zone.

Further, the truck 10 may comprise one or more load presence sensors 53,see FIG. 13. The load presence sensor(s) 53 may comprise proximity orcontact technology, e.g., a contact switch, a pressure sensor, anultrasonic sensor, optical recognition device, infrared sensor or othersuitable technology that detects the presence of a suitable loadcarrying structure 55, e.g., a pallet or other platform, collectioncage, etc. The controller 103 may refuse to implement a travel commandif one or more of the load presence sensors 53 indicate that the loadplatform 55 is not in a valid designated position. Still further, thecontroller 103 may communicate with the brake controller 108 to stop thetruck 10 if the load presence sensors 53 detect a change of the loadplatform 55 from a valid designated position.

It should be understood that any number of detection zones may beimplemented, and the implemented detection zones may overlap or definediscrete, mutually exclusive zones. Depending upon the sensor and sensorprocessing technologies utilized, the input(s) to the controller 103designating an object in the steer bumper zones 132A, 132B may be inother formats. As yet a further illustration, the first and second lasersteer bumper zones 132A, 132B may be defined by both ultrasonic sensorsand one or more laser sensors. For example, the laser sensor 2000 may beutilized as a redundant check to verify that the ultrasonic sensorsproperly detect an object in either the left or right steer bumper zones132A, 132B, or vice versa. As yet a further example, ultrasonic sensorsmay be utilized to detect an object in the left or right steer bumperzones 132A, 132B and the laser sensor 2000 may be utilized todistinguish or otherwise locate the object to determine whether theobject was detected in the left steer bumper zone 132A or the rightsteer bumper zone 132B. Other arrangements and configurations mayalternatively be implemented.

If a steer bumper zone warning designates that an object is detected inthe left steer bumper zone 132A, then a steer correction routine isimplemented at 156 that includes computing a steer angle correction tosteer the truck 10 to the right according to a first set of parameters.By way of illustration and not by way of limitation, a steer rightcorrection implemented at 156 may include steering the truck 10 to theright at a right direction steer angle. In this regard, the rightdirection steer angle may be fixed or variable. For example, thecontroller 103 may command the steer controller 112 to ramp up to somedesired steer angle, e.g., 8-10 degrees to the right. By ramping up to afixed steer angle, sudden changes in the angle of the steer wheel(s)will not occur, resulting in a smoother performance. The algorithmaccumulates the distance traveled at the steer correction angle, whichmay be a function of how long the appropriate steer bumper input isengaged.

According to various aspects of the present invention, the steered wheelangular change may be controlled to achieve, for example, asubstantially fixed truck angle correction as a function of accumulatedtravel distance. The travel distance accumulated while performing asteer correction maneuver may be determined based upon any number ofparameters. For example, the distance traveled during the steercorrection may comprise the distance traveled by the truck 10 until thedetected object is no longer within the associated left bumper detectionzone 132A. The accumulated travel distance may also/alternativelycomprise, for example, traveling until a time out is encountered,another object is detected in any one of the bumper or detection zones,and/or predetermined maximum steer angle is exceeded, etc.

Upon exiting a right steer correction at 156, e.g., by maneuvering thetruck 10 so that no object is detected within the left steer bumperdetection zone 132A, a left steer compensation maneuver is implementedat 158. The left steer compensation maneuver at 158 may comprise, forexample, implementing a counter steer to adjust the travel direction ofthe truck 10 to an appropriate heading. For example, the left steercompensation maneuver may comprise steering the truck 10 at a selectedor otherwise determined angle for a distance that is a percentage of thepreviously accumulated travel distance. The left steer angle utilizedfor the left steer compensation maneuver may be fixed or variable, andmay be the same as, or different from the steer angle utilized toimplement the right steer correction at 156.

By way of illustration and not by way of limitation, the distanceutilized for the left steer compensation maneuver at 158 may beapproximately one quarter to one half of the accumulated travel distancewhile implementing the right steer correction at 156. Similarly, theleft steer angle to implement the left steer compensation maneuver maybe approximately one half of the angle utilized to implement the rightsteer correction at 156. Thus, assume that the right steer angle is 8degrees and the accumulated steer correction travel distance is 1 meter.In this example, the left steer compensation may be approximately onehalf of right steer correction, or −4 degrees, and the left steercompensation will occur for a travel distance of approximately ¼ metersto ½ meters.

The particular distance and/or angle associated with the left steercompensation maneuver at 158 may be selected, for example, so as todampen the “bounce” of the truck 10 as the truck 10 moves along itscourse to steer correct away from detected obstacles. As anillustration, if the truck 10 steer corrects at a fixed degrees perdistance traveled, the controller 103 may be able to determine how muchthe corresponding truck angle has changed, and therefore, adjust theleft steer compensation maneuver at 158 to correct back towards theoriginal or other suitable heading. Thus, the truck 10 will avoid “pingponging” down an aisle and instead, converge to a substantially straightheading down the center of the aisle without tedious manualrepositioning required by the truck operator. Moreover, the left steercompensation maneuver at 158 may vary depending upon the particularparameters utilized to implement the right steer correction at 156.

Correspondingly, if a steer bumper zone warning designates that anobject is detected in the right steer bumper zone 132B, then a steercorrection routine is implemented at 160 that includes computing a steerangle correction to steer the truck 10 to the left according to a secondset of parameters. By way of illustration and not by way of limitation,a steer left correction implemented at 160 may include steering thetruck 10 to the left at a left steer angle. In this regard, the leftsteer correction maneuver at 160 may be implemented in a manneranalogous to that described above at 156, except that the correction isto the right at 156 and to the left at 160.

Similarly, upon exiting a left steer correction at 160, e.g., bymaneuvering the truck 10 so that no object is detected within the rightbumper detection zone 132B, a right steer compensation maneuver isimplemented at 162. The right steer compensation maneuver at 162 maycomprise, for example, implementing a counter steer to adjust the traveldirection of the truck 10 to an appropriate heading in a manneranalogous to that described at 158, except that the steer compensationmaneuver at 158 is to the left and the steer compensation maneuver at162 is to the right.

After implementing the steer compensation maneuver at 158 or 162, thetruck may return to a substantially straight heading, e.g., 0 degrees at164 and the process loops back to the beginning to wait for thedetection of another object in either of the steer bumper zones 132A,132B.

The algorithm can further be modified to follow various control logicimplementations and/or state machines to facilitate various anticipatedcircumstances. For example, it is possible that a second object willmove into either steer bumper zone 132A or 132B while in the process ofimplementing a steer compensation maneuver. In this regard, the truck 10may iteratively attempt to steer correct around the second object. Asanother illustrative example, if object(s) are simultaneously detectedin both the left and right steer bumper zones 132A, 132B, the controller103 may be programmed to maintain the truck 10 at its current heading(e.g., zero degree steer angle), until either one or more steer bumperzones 132A, 132B are cleared or the associated detection zones cause thetruck 10 to come to a stop.

According to further aspects of the present invention, a user and/orservice representative may be able to customize the response of thesteer angle correction algorithm parameters. For example, a servicerepresentative may have access to programming tools to load customizedvariables, e.g., in the controller 103, for implementing steercorrection. As an alternative, a truck operator may have controls thatallow the operator to input customized parameters into the controller,e.g., via potentiometers, encoders, a software user interface, etc.

The output of the algorithm illustrated in FIG. 12 may comprise, forexample, an output that defines a steer correction value that may becoupled from the controller 103 to an appropriate control mechanism ofthe truck 10. For example, the steer correction value may comprise a +/−steer correction value, e.g., corresponding to steer left or steerright, that is coupled to a vehicle control module, steer controller112, e.g., as illustrated in FIG. 2, or other suitable controller. Stillfurther, additional parameters that may be editable, e.g., to adjustoperational feel may comprise the steer correction angle, a steercorrection angle ramp rate, a bumper detection zone size/range for eachsteer bumper zone, truck speed while steer correcting, etc.

Referring to FIG. 13, assume in the illustrative example, that the truck10 is traveling in response to receiving a remote wireless travelrequest and that before the truck 10 can travel a predetermined jogdistance, the truck 10 travels into a position where a rack leg 1720 anda corresponding pallet 1740 are in the path of the left steer bumperzone 132A. Keeping with the exemplary algorithm of FIG. 12, the truck10, e.g., via the controller 103, may implement an obstacle avoidancemaneuver by entering a steer correction algorithm, to steer the truck tothe right. For example, the controller 103 may compute or otherwiselookup or retrieve a steer correction angle that is communicated to asteer controller 112 to turn the drive wheel(s) of the truck 10.

The truck 10 maintains steer correction until an event occurs, such asthe disengagement of the object, e.g., when the scanning laser or otherimplemented sensor technology no longer detects an object in the leftsteer bumper zone 132. Assume that the truck 10 accumulated a traveldistance of one half of a meter during the steer correction maneuver,which was fixed at 8 degrees. Upon detecting that the left steer bumperzone signal has disengaged, a counter steer compensation is implementedto compensate for the change in heading caused by the steer correction.By way of example the steer compensation may steer the truck 10 to theleft for approximately one quarter meter accumulated travel distance, at4 degrees. For very narrow aisles, the Left/Right steer bumper zonesensors may provide very frequent inputs/little time between sensescompared to relatively wider aisles.

The various steer angle corrections and corresponding counter steercompensations may be determined empirically, or the angles, ramp rates,accumulated distances, etc., may be computed, modeled or otherwisederived.

In the illustrative arrangement, the system will try to maintain thetruck 10 centered in the aisle as the truck 10 advances in response toreceiving a corresponding wirelessly transmitted travel request by thetransmitter 70. Moreover, bounce, e.g., as measured by the distance fromthe centerline of a warehouse aisle, is damped. Still further, there maybe certain conditions where the truck 10 may still require some operatorintervention in order to maneuver around certain objects in the line oftravel.

Referring now to FIG. 14, a materials handling vehicle, which isillustrated as a low level order picking truck 1010 includes in general,a load handling assembly 1012 that extends from a power unit 1014. Theload handling assembly 1012 includes a pair of forks 1016, each fork1016 having a load supporting wheel assembly 1018. The load handlingassembly 1012 may include other load handling features in addition to,or in lieu of the illustrated arrangement of the forks 1016, such as aload backrest, scissors-type elevating forks, outriggers and separateheight adjustable forks, a mast, a load platform, collection cage orother support structure carried by the forks 1016 or otherwise providedfor handling a load supported and carried by the truck 1010.

The illustrated power unit 1014 comprises an operator's area 1030 havinga first end section 1032 positioned opposite the forks 1016, a secondend section 1034 positioned adjacent to the forks 1016 and astep-through operator's station 1036 dividing the first end section 1032from the second end section 1034. A first work area is provided towardsthe first end section 1032 of the power unit 1014 and includes a controlarea 1040 for driving the truck 1010 and for controlling the features ofthe load handling assembly 1012. The first end section 1032 may alsooptionally comprise a first storage area 1046, e.g., for securing looseitems that a corresponding truck operator may wish to keep track of. Thefirst end section 1032 also defines a compartment 1048 for containing abattery, control electronics and motor(s), such as a traction motor,steer motor and lift motor for the forks (not shown).

As shown for purposes of illustration, and not by way of limitation, thecontrol area 1040 comprises a handle 1052 for steering the truck 1010,which may include controls such as grips, butterfly switches,thumbwheels, rocker switches, a hand wheel, a steering tiller, etc., forcontrolling the acceleration/braking and travel direction of the truck1010. For example, as shown, a control such as a switch grip 1054 may beprovided on the handle 1052, which is spring biased to a center neutralposition. Rotating the switch grip 1054 forward and upward will causethe truck 1010 to move forward, e.g., power unit 1014 first, at a speedproportional to the amount of rotation of the switch grip 1054.Similarly, rotating the switch grip 1054 toward the rear and downward ofthe truck 1010 will cause the truck 1010 to move in reverse, e.g., forks1016 first, at a speed proportional to the amount of rotation of theswitch grip 1054. Devices may also be provided for sounding a horn orfor performing other truck functions.

The step-through operator's station 1036 provides a platform 1056 uponwhich an operator may stand to drive the truck 1010 and operate the loadhandling features of the truck 1010. Presence sensors 1058 may also beprovided, e.g., on, above, or under the platform 1056 or otherwiseprovided about the operator's station 1036, to detect the presence of anoperator on the truck 1010 as will be explained in greater detailherein. In the exemplary truck of FIG. 14, the presence sensors 1058 areshown in dashed lines indicating that they are positioned under theplatform 1056. Under this arrangement, the presence sensors 1058 maycomprise load sensors, switches, etc. As an alternative, the presencesensors 1058 may be implemented above the platform 1056, such as byusing ultrasonic, capacitive or other suitable sensing technology.

The second end section 1034 of the power unit 1014 may comprise anoperator rest pad or other suitable support structure, a grab bar 1062and a second storage area 1064. An antenna 1066 is provided forreceiving control signals from a corresponding remote control device1070, which in one embodiment comprises a transmitter, a power pack, anda control structure, as will be described in greater detail herein. Asshown, radio frequency (RF) performance is facilitated by coupling theantenna 1066 to the second end section 1034 of the power unit 1014,e.g., along or otherwise proximate to a vertically extending post 1067that may also support a light source 1068. The placement of the antenna1066 above the light source 1068 on the post 1067 provides a convenientlocation for promoting RF reception and may eliminate variability fromthe light source 1068 and its associated wires running past the antenna1066. Alternatively, the antenna 1066 can be positioned anywhere else onthe truck 1010. The light source 1068 may be utilized to provideinformation about the state of the truck 1010 and/or state of wirelesscommunication between a properly paired wireless remote control and thetruck. For example, the light may illuminate when the truck 1010 is inmotion and blink or illuminate in defined patterns to indicateprescribed conditions.

The grab bar 1062 may be used by the operator as a grasping surface,e.g., when entering, exiting or operating the truck 1010. Additionally,the grab bar 1062 and other included posts, e.g., an additional optionalgrab bar towards the first end section 1032 (not shown) may be furtherutilized, for example, to support accessories such as scanners,computers, radios, communications devices and other electronics, lights,clipboards, fans, storage units and other work or convenience relatedaccessories, or other required items for performing intended taskswithin an application. For example, the grab bar 1062, or second endsection 1034 in general, may be used to mount supplemental operationalcontrols.

The exemplary truck 1010 is provided for illustration and not by way oflimitation. In practice, the truck 1010 may be implemented in otherformats, styles and features, such as an end control pallet truck thatincludes a steering tiller arm that is coupled to a tiller handle forsteering the truck. In this regard, the truck 1010 may have similar oralternative control arrangements to that shown in FIG. 14.

In addition to or in lieu of the light source 1068, an indicator, e.g.,audible, visible etc., may be associated with the remote control systemas will be described in greater detail herein. For example, as shown,the truck 1010 may include an indicator such as a strobe light 1072,which is illustrated as being positioned on or adjacent to the secondend section 1034 of the power unit 1014 mounted relatively low to theground. The indicator may alternatively be mounted in any otherpractical location, e.g., on a load backrest, on a vertically extendingpole such as the light source 1068, or other part of the truck 1010.

The strobe light 1072 may be set to a unique pattern that is associatedwith remote control operation. As such, when the truck 1010 is notoperating under wireless remote control, the strobe pattern can changerelative to when the truck 1010 is operating under wireless remotecontrol. For example, the strobe light 1072 may be turned off or changedin intensity, pattern etc. when the truck 1010 is not under wirelessremote control. Comparatively, the strobe can flash when the truck 1010is under wireless remote control. The speed, intensity or other patternscan vary based upon the operating conditions of the truck, e.g., toindicate motion, fault conditions, etc. As illustrated, the lightpattern 1074 from the strobe light 1072 is directed generally downwardat an angle towards the forks 1016. As such, the strobe area is notdistracting to the operator or to other people in the vicinity of thetruck 1010, e.g., in the working aisle of the truck 1010, yet isapparent and visible to the operator and other people in the vicinity ofthe truck 1010.

The truck 1010 may also comprise one or more object sensors 1076, whichare provided about the truck 1010, e.g., towards the first end section1032 of the power unit 1014 and/or to the sides of the power unit 1014.The object sensors 1076 may comprise any suitable proximity or contactdetection technology, such as an ultrasonic sensors, optical recognitiondevices, infrared sensors, laser sensors, etc. For example, the objectsensors 1076 may be implemented by Bosch URF6 ultrasonic sensors and acorresponding controller.

The object sensors 1076 may be used to detect the presence of objectswithin a predefined area of the power unit 1014, such as within apredefined detection area 1078 as illustrated in dashed lines. Inpractice, the range of each object sensor 1076 may be different, and thesensor detection areas 1078 may overlap or otherwise be arranged,depending upon the specific implementation and selection of proximitydetecting technology. For example, the object sensors 1076 towards thefront of the power unit 1014 may have a range of approximately 0-5 feet(0-1.5 meters) and the object sensors 1076 to the sides of the powerunit 1014 may have a range of approximately 0-2 feet (0-0.6 meters).Moreover, the detection range of the object sensors 1076 may beadjustable or be otherwise made dynamically variable. For example, therange of the object sensors 1076 may be extended if certain operatingconditions are detected, etc. As an example, the range of the objectsensors 1076 may be adjusted based upon the speed of the truck 1010 whenadvancing under wireless remote control.

Further, the truck 1010 may comprise one or more load presence sensors1080. The load presence sensor(s) 1080 may comprise proximity or contacttechnology, e.g., a contact switch, a pressure sensor, an ultrasonicsensor, optical recognition device, infrared sensor or other suitabletechnology that detects the presence of a suitable load carryingstructure, e.g., a pallet or other platform, collection cage, etc. Theload presence sensor(s) 1080 may be mounted towards the front of thepower unit 1014, to a load backrest or other suitable support structure,the location of which will likely depend upon the technology deployed.

Referring to FIG. 15, a block diagram illustrates a control arrangementfor integrating remote control commands with the truck 1010. The antenna1066 is coupled to a receiver 1102 for receiving commands issued by theremote control device 1070. The receiver 1102 passes the receivedcommands to a controller 1103, which implements the appropriate actionsin response to the received commands, e.g., by operating relays or otheractuation devices controlled by electricity, magnetics, hydraulics,pneumatics, etc., or by communicating with other truck components. Thecontroller 1103 may also receive other inputs 1104 from other sources,such as switches, encoders and other input devices available to thetruck 1010 to determine appropriate action in response to the receivedcommands from the remote control device 1070.

In one exemplary arrangement, the remote control device 1070 isoperative to wirelessly transmit a travel request as first type signal,also referred to herein as a “travel signal” or “go signal” to thereceiver on the truck 1010. The travel request is used to request thetruck 1010 to advance or jog in a first direction. The first directionmay be defined, for example, by movement of the truck 1010 in a powerunit 1014 first, i.e., forks 1016 to the back, direction. However, otherdirections of travel may alternatively be defined. Moreover, the truck1010 may be controlled to travel in a generally straight direction oralong a previously determined heading.

The first type signal is received by the receiver 1102 and iscommunicated to the controller 1103. If the controller 1103 determinesthat the travel signal is a valid travel signal and that the currentvehicle conditions are appropriate (explained in greater detail herein),the controller 1103 sends a signal to the appropriate controlconfiguration of the particular truck 1010 to advance and then stop thetruck 1010. As described herein, stopping the truck 1010 may beimplemented by either allowing the truck 1010 to coast to a stop or byapplying a brake to stop the truck.

As an example, the controller 1103 may be communicably coupled to afraction control system, illustrated as a traction motor controller 1106of the truck 1010. The controller is responsive to receipt of the firsttype signal by the receiver 1102 to evaluate at least one vehiclecondition, to decide whether to implement the travel request based uponthe evaluation of the vehicle condition(s) and to cause the tractioncontrol system to advance the truck 1010 if the controller decides toimplement the travel request based upon the evaluation of thecondition(s).

The traction motor controller 1106 is coupled to a traction motor 1107that drives at least one steered wheel 1108 of the truck 1010. Thecontroller 1103 may communicate with the traction motor controller 1106in such a way so as to limit the speed of the truck 1010 in response toreceiving a travel request from the remote control device 1070. Forexample, the travel speed of the truck 1010 may be limited to typicalwalking speed, e.g., up to or around 2.75 miles per hour (4.4 kilometersper hour).

There may be noise and/or interference, e.g., from other wireless andremote control systems in the vicinity of the truck 1010. As such,either the receiver 1102 or the controller 1103 may perform signalanalysis to discriminate valid travel signals from invalid signals. Forexample, the controller 1103 may determine that the receiver 1102 hasprovided a travel signal at an improper frequency or on an improperchannel. Moreover, an operator and/or transmitter identification (ID)code may be embedded into the travel request. Under such a case, thecontroller 1103 may be operatively configured to respond to messagesbearing only certain ID codes or to exclude/disregard commands fromcertain ID codes.

Also, the travel signal may be detected at a power level that is toostrong or too weak to be considered a valid signal. For example, if asignal is too strong, it may indicate that an operator is too close tothe truck 1010 to initiate automated travel. Correspondingly, if asignal is too weak, that may indicate that an operator has exceeded apredetermined range from the truck 1010 for allowed remote control.

Still further, the controller 1103 may require an acknowledgement signalor other bi-directional communication from the remote control device1070 that was not timely received. For example, the controller 1103 maybe coupled to a transmitter 1109 on the truck 1010 to facilitatebi-directional communication with the wireless remote control device1070. Under these and other similar circumstances, the controller 1103may opt to disregard a received travel request and not take action ifthe bi-directional communication is not properly confirmed. Stillfurther, bi-directional communication may be utilized for pairing thereceiver 1102 in the truck 1010 to a corresponding instance of awireless remote control device 1070.

The controller 1103 may also refuse to acknowledge the travel signaldepending upon vehicle condition(s) that relate to environmental oroperational factors. For example, the controller 1103 may disregard anotherwise valid travel request based upon information derived from oneor more of the sensors 1058, 1076, 1080. In this regard, the sensors1058, 1076, 1080 etc. may be coupled to the controller 1103 via theinputs 1104 or via a suitable truck network, such as a control areanetwork (CAN) bus 1110. Any other number of reasonable conditions mayalso/alternatively be implemented by the controller 1103 to interpretand take action in response to received signals.

The CAN bus 1110 facilitates a convenient platform for the controller1103 of the truck 1010 to communicate with any truck system or moduleconnected to the CAN bus 1110 to make decisions as to how to implementcommands received from the remote control device 1070. Moreover,relevant information derived from the truck 1010 can be communicatedback to the remote control device 1070 by utilizing the transmitter 1109in the truck 1010 to communicate with a corresponding receiver in theremote control device 1070.

The CAN protocol is a convenient network platform for material handlingvehicles as there is no addressing of subscribers or stations in theconventional network sense. Rather, the CAN defines a prioritized systemof transmitted messages where the priority of a given message broadcastacross the CAN bus 1110 is dependent upon a corresponding messageidentifier code. A message broadcast from a first module can be receivedby all nodes or modules connected to the CAN bus 1110. Thus, thecontroller 1103 can make intelligent decisions with regard to wirelessremote control and/or to the exchange of information with acorresponding paired wireless remote control device 1070 based upon anynumber of factors, states, conditions, etc., that can be conveyed acrossthe CAN bus 1110.

The network may alternatively comprise any other bus system, e.g., aLocal Interconnect Network (LIN) or a Vehicle Area Network (VAN), etc.,or communications capabilities, such as a wiring harness, bus othersignal propagation manner or other control network. As such, the variouscontrollers and electronics on the truck 1010 may broadcast, unicast orotherwise communicate with each other.

Upon acknowledgement of a valid travel request, the controller 1103interacts with the traction motor controller 1106, e.g., via the CAN bus1110 or other communication coupling, to advance the truck 1010.Depending upon the particular implementation, the controller 1103 mayinteract with the traction motor controller 1106 to advance the truck1010 by a predetermined distance. Alternatively, the controller 1103 mayinteract with the traction motor controller 1106 to advance the truck1010 for a period of time in response to the detection and maintainedactuation of the control on the remote control device 1070. Further, thetruck 1010 may be configured to jog for as long as a travel controlsignal is received. However, the controller 1103 may further beconfigured to “time out” and stop the travel of the truck 1010 basedupon a predetermined event, such as exceeding a predetermined timeperiod or travel distance regardless of whether maintained actuation ofa corresponding control on the remote control device 1070. Other controlarrangements may alternatively be implemented for effecting the range,duration, speed, etc. of the truck 1010 when operating under wirelessremote control, examples of which will be set out in greater detailherein.

The controller 1103 may also communicate, e.g., via the CAN bus 1110 orotherwise, with a steer control system to cause the truck 1010 to adjusta travel path of the truck 1010. For example, the controller 1103 maycommunicate with a steer controller 1112 to command or otherwise controla steer motor 1114 or other suitable control device, which also couplesto the steered wheel(s) 1108 of the truck 1010. For example, thecontroller 1103 may straighten out the truck 1010, or adjust a steerangle of the truck 1010 before or during a wireless remote controlinitiated travel operation. As such, the controller 1103 may default toa mode of operation wherein the truck 1010 travels in a straightdirection or along a predetermined heading when the truck 1010 is movingunder wireless remote control in response to receipt of a travelrequest. The controller 1103 may further impose a steer angle limitduring remote control operations if the truck 1010 is to travel in adirection where the steered wheel(s) 1108 is not straight. For example,the controller 1103 may limit the angle that the truck 1010 can travelwhen executing remote controlled travel requests to a range ofapproximately 5 to 10 degrees. Thus, in addition to jogging the tractionmotor 1107, the controller 1103 may also straighten out or otherwiseadjust or control the steered wheel 1108.

The remote control device 1070 may also be operative to transmit asecond type signal, such as a “stop signal”, designating that the truck1010 should brake and/or otherwise come to rest. The second type signalmay also be implied, e.g., after implementing a “travel” command. Thesecond type signal is received by the receiver 1102 and is communicatedto the controller 1103. If the controller 1103 determines that the stopsignal is a valid stop signal, the controller 1103 sends a signal to abrake control system, e.g., via the CAN bus 1110 or otherwise. Forexample, the controller 1103 may communicate with a brake controller1116 of the truck 1010 to cause an appropriate brake arrangement 1117 tobring the truck 1010 to rest. As an alternative to a stop signal, thesecond type signal may comprise a “coast signal”, designating that thecoast should allow the truck 1010 to eventually come to rest. Forexample, if a coast signal is recognized by the controller 1103 as avalid coast signal, then the controller 1103 may disengage drive to thetruck 1010, e.g., by instructing the traction controller 1106 to stopapplying a signal to drive the traction motor 1107, but otherwise allowthe truck 1010 to coast and gradually slow to a stop. Any number ofreasonable conditions or factors may be considered by the controller1103 to interpret and take action in response to received stop or coastsignals. Further, rather than the remote control device 1070transmitting a second type signal to request that the truck 1010implement a particular function, the remote control device 1070 maytransmit multiple instances of the first type signal, i.e., if a buttonon the remote control device 1070 is “double clicked”, to request thatthe truck 1010 implement a particular function, as will be discussedbelow.

The time that it takes to bring the truck 1010 to a complete rest mayvary, depending for example, upon the intended application, theenvironmental conditions, the capabilities of the particular truck 1010and other similar factors. For example, after completing an appropriatejog movement, it may be desirable to allow the truck 1010 to “coast”some distance before coming to rest so that the truck 1010 stops slowly.This may be achieved by utilizing regenerative braking to slow the truck1010 to a stop so that a predetermined range of travel distances may beachieved from the initiation of the stop operation until the time inwhich the truck finally comes to rest. Alternatively, a brakingoperation may be applied after a predetermined delay time to allow apredetermined range of additional travel to the truck 1010 after theinitiation of the stop operation. It may also be desirable to bring thetruck 1010 to a relatively quicker stop, e.g., if an object is detectedin the travel path of the truck 1010 or if an immediate stop is desiredafter a successful jog operation. For example, the controller may applypredetermined torque to the braking operation. Under such conditions,the controller 1103 instructs the brake controller 1116 to apply thebrake arrangement 1117 to stop the truck 1010.

Moreover, if a truck disable function is implemented, the truck 1010 maystop with maximum braking torque. For example, the remote control device1070 may include a disable control that transmits a message instructingthe truck 1010 to brake and/or shut down. In response to the disablefunction, the truck 1010 may also switch off a main contactor 1118 thatis utilized to power up the truck 1010. Under this arrangement, thetruck 1010 may require a restart operation, e.g., by using a key switchor other suitable configuration to re-initiate a truck startupprocedure. The controller 1103 may also interact with other truckoutputs 1119 to implement desired activities, e.g., to control a horn,light source, display, etc. As such, the controller 1103 may interactwith various components of the truck 1010, with the operator and withwireless remote control devices 1070 to implement various traveling,stopping, coasting and power enabling strategies.

As noted above, the controller 1103 may communicate with the brakecontroller 1116 to cause the brake arrangement 1117 to bring the truck1010 to rest under various conditions. For example, the outputs of theobject sensors 1076 may be overridden while the operator is driving thetruck 1010, for example, to allow the operator to navigate the truck1010 in tight spaces and around corners that might otherwise activateone or more of the object sensors 1076. However, the outputs of theobject sensors 1076 may be effective and not overridden when no operatoris sensed on the truck 1010. As such, the controller 1103 maycommunicate with the brake controller 1116 to stop the truck 1010 if thecontroller 1103 determines that an object is in the path of travel ofthe truck 1010, e.g., as detected by the object sensors 1076 duringtravel in response to receiving a remote travel request from the remotecontrol device 1070.

Additionally, the controller 1103 may refuse to implement a travelrequest in response to receiving a travel signal from a correspondingremote control device 1070 if the platform presence sensor(s) 1058detect the presence of an person on the truck, or where the loadpresence sensors 1080 indicate that a corresponding load platform, e.g.,a pallet, is not in position on the forks 1016 of the truck 1010. Stillfurther, the controller 1103 may communicate with the brake controller1116 to stop the truck 1010 if the load presence sensors 1080 detect achange of the load platform from a valid designated position.

The remote control device 1070, the receiver 1102 and the transmitter1109 may communicate over a range of frequencies, thus allowing theremote control device 1070 and corresponding truck 1010 to lock onto afrequency or frequencies that have minimal interference from outsidesources. Additionally, any number of wireless technologies may beutilized to facilitate interaction between the truck 1010 and the remotecontrol device 1070, including the use of spread spectrum technologies.

As an example, technologies such as a Bluetooth communications link or aderivative thereof, may be formed between the transmitter in the remotecontrol device 1070 and the receiver 1102 on the truck 1010. TheBluetooth and similar communication technologies allow control overremote output power intensity, adjustable output power, multiplesub-channels and frequency hopping to reduce the likelihood of noise andother interference in the work area. Bluetooth bandwidth may alsosimplify transmission of voice control, as described in greater detailherein.

If the truck 1010 includes a tiller arm instead of the illustratedsteering control, the truck may include a steering arm brake. As such, asteering arm locking device may be provided for placing the truck into acoast mode of operation when using the remote, for example, as disclosedin U.S. Pat. No. 6,595,306, assigned to the same assignee, and which isherein incorporated by reference.

Referring to FIG. 16, the remote control device 1070 and thecorresponding receiver 1102 may be configured so that wireless controlis operable over a predetermined distance. The truck 1010 is situated ina typical warehouse aisle 1120 having a plurality of storage locations1122 on either side of the aisle 1120. As illustrated, the remotecontrol device 1070 is capable of communicating with the truck 1010 overa range designated by the dashed path radius 1130. The range may varydepending upon a particular implementation. For example, a range ofoperation may depend upon an anticipated distance that an operator isexpected to walk from the truck 1010 to pick an item during a pickingprocess. In an illustrative example, this distance may be approximately25 feet (7.62 meters). Moreover, the range of operation need not be thesame in all directions or under all conditions. For example, the rangeof operation may have a pattern that is elliptical or in some otherdirectional pattern, etc. Still further, there may be a minimum range,within which the wireless remote control device 1070 may benonfunctional. As described above, the controller 1103 may discriminatesignals that are too strong, suggesting that the operator is eitherstanding on, or is in too close of proximity to the truck 1010 forremote operation. As yet another example, the operation range may beaffected by operating conditions and environmental conditions, such asthe speed of the truck 1010, where the truck 1010 is located within afacility, etc.

It may be desirable to set or otherwise program the range of the objectsensors 1076 for detecting obstacles in the path of the truck 1010,which is traveling in response to receiving a travel request from theremote control device 1070. For example, as shown, each of the objectsensors 1076 are set to detect objects in their path within a distance,which is schematically suggested by the range designated by the dasheddetection area 1078 proximate to each object sensor 1076. Theside-located object sensors 1076 are not illustrated in FIG. 16 forclarity of discussion. The range of the object sensors 1076 may also beconfigured to change, either statically or dynamically. For example, therange of the object sensors 1076 may change as the speed of the truck1010 changes in response to received jog commands, etc.

For each actuation of the travel request on the remote control device1070, the operator can advance the truck 1010 without taking the time tophysically engage the controls on the truck 1010. For example, uponissuing a travel request via the remote control device 1070, theoperator may walk towards the next item to be retrieved, or perform someother task. The truck 1010 automatically travels forward by an amountcorresponding to the travel request. For example, if travel for apredetermined distance is commanded, after traveling the predetermineddistance, the truck 1010 stops, without requiring a separate controlaction from the operator. Alternatively, the truck 1010 may stay inmotion for as long as a jog command is issued by the remote controldevice 1070, e.g., by maintained actuation of a travel button. Underthis later configuration, the truck 1010 continues to travel until theoperator releases the travel button, the operator engages a stop orcoast button, a specified maximum continuous travel time expires, orsome other appropriate action stops the truck 1010.

As an example of a first optional manner in which an operator caninteract with the truck 1010, assume that an operator travels with thetruck 1010 down the aisle 1120. A first row 1142 of storage locations1122 is located on a first side of the truck 1010. A second row 1144 ofstorage locations 1122 is located on a second side of the truck 1010.Each of the first and second rows 1142, 1144 of storage locations 1122include a plurality of individual storage areas, which may be bins,pallets, delineated or otherwise designated areas, etc. Moreover, eachstorage location 1122 may comprise several independent storage areasthat are vertically stacked, such as in a racking system in a warehousefacility or distribution center. As such, there may be multiple levelsof storage at each storage location 1122. During automatic operation ofthe truck via the remote control device 1070, the truck 1010 travelsdown the aisle 1120. For example, the truck 1010 is illustratedtraveling with the power unit 1014 forward as illustrated by thedirectional arrow 1132. Thus, the forks 1016 are towards the back of thetruck 1010 when traveling under remote control. Other travel directionsmay be alternatively implemented.

Assume that the operator is initially located at position A, and that anitem is to be picked from a storage location 1122 designated as storagelocation “1122-1” in row 1144. The operator walks from position A to thestorage location “1122-1” to retrieve the desired pick item. Afterpicking the desired contents, the operator is at position B, which isjust in front of storage location “1122-1”. It is further assumed thatthe operator has advanced or is in the process of advancing the truck1010 using the remote control device 1070 such that a load platform 1146that is situated on the forks 1016 of the truck 1010 is located atposition C, which is in the vicinity of position B. The operator neednot carry any item(s) of the pick order to the truck 1010 when walkingfrom position A to storage location “1122-1”. Moreover, by the time thatthe operator arrives at position B with the item(s) picked from storagelocation “1122-1” (or shortly before or thereafter), the truck 1010 hascome to rest at position C. Thus, the operator need only carry the pickitem(s) a relatively short distance from storage location “1122-1 toposition B.

After placing the pick onto the load platform 1146 of the truck 1010,the operator may then step onto the truck 1010 to drive to the nextlocation, or if there are additional items to be picked in the currentaisle 1120, the operator may move the truck 1010 using the travelcontrol of the remote control device 1070.

Continuing with the above example, it is assumed that the operator isnow located at position B, and that an item is to be picked from astorage location 1122 designated as storage location “1122-2” in row1142. The operator walks from position B to storage location “1122-2” toretrieve the desired pick item. Moreover, the operator initiates awireless remote control travel request, e.g., by using the remotecontrol device 1070 to wirelessly transmit a first type (“travel”)signal to the receiver on the truck 1010. By the time that the operatorarrives at position D with the item picked from storage location“1122-2” (or shortly before or thereafter), the truck 1010 has traveledunder wireless remote control from position C and has come to rest atposition E, which is in the vicinity of position D. Again, the operatorplaces the retrieved item on the load platform 1146 of the truck 1010 ina manner that minimizes the distance that the operator must walk whilecarrying items on the pick order.

Moreover, by moving the truck 1010 foreword while picking, the timerequired to pick from a given aisle 1120 can be reduced because theoperator need not interrupt the pick process to reposition or reorientthe truck 1010. Still further, as schematically illustrated, a singleactuation of a travel control on the remote control device 1070 maycause the truck 1010 to advance a distance 51 and then stop. As such,after actuating the travel control via the remote control device 1070,the truck 1010 is positioned in a convenient place for the operator toplace previously retrieved items in a manner that minimizes the distancethat the operator must carrying the picked item(s). Moreover, becausethe operator need not disrupt picking or other work related tasks, theoperator may save energy and time in completing a given task, e.g.,compared with an operation wherein the operator is required tocontinually stop working to advance the truck to its next location.

One measure of productivity of an operator is the time that the operatorspends at the pick face. That is, how much time is spent picking orderscompared to time spent relocating the truck 1010 and performing othertasks not immediately related to locating and loading pick items. As isevident in the discussion above, the time required to relocate the truck1010 has been reduced allowing the operator to spend more time pickingitems. Moreover, the truck 1010 can be remotely controlled to alwaysstay in front of the operator, allowing the operator to work towards aload carrying portion of the truck 1010. This minimizes the distancethat the operator must travel to fetch and load pick items, and furtherreduces the distance that the operator must walk while carrying the pickitems. This may become significant, especially where the forks 1016 ofthe truck 1010 are relatively long. For example, certain forks 1016 cansupport triple length loads, such as three pallets.

Moreover, warehouse management system software that directs operators intheir picking operations can take into account the remote travel controlof the truck 1010 when planning pick orders so that the advantages ofthe remote control can be further enhanced by more efficient computerprocessing when preparing the pick orders.

Referring to FIG. 17, according to an aspect of the present invention,additional features may be incorporated into the warehouse or otherfacility and/or to the truck 1010 to provide enhanced functionalities.For example, the wireless remote jog control functionality may bedisabled in certain locations about a facility, such as at the end ofaisles, at crossing or intersecting passageways, at loading or receivingdock areas, at areas of high pedestrian traffic, etc. To illustrate thisfeature, assume that wireless remote jog control is to be disabled onthe truck 1010 as the truck 1010 approaches the end of an aisle 1120. Tofacilitate disabling wireless remote jog control of the truck 1010 at apredetermined location, the truck 1010 includes one or more devices1148, such as radio frequency identification (RFID) antennas.Corresponding RFID tags 1150 are positioned at the end of the aisle at asuitable position.

The devices 1148 generate signals in response to detecting the end ofthe aisle 1120, e.g., by sensing the corresponding RFID tags 1150, whichtrigger the truck 1010 to stop if it is under wireless remote jogcontrol. For example, signals from the devices 1148 may couple tocorresponding inputs, e.g., appropriate ones of the inputs 1104 on thecontroller 1103. For example, if the controller 1103 detects anappropriate signal from one of the devices 1148 and the controller 1103detects that it is currently operating the truck 1010 in response to atravel request from the remote control device 1070, the controller 1103may issue an appropriate command to the brake controller 1116 to stopthe truck 1010.

In the illustrated example, the aisle 1120 is 15 feet (approximately 4.6meters) wide and the RFID antennas 148 are configured to detect thecorresponding RFID tags 1150 within a radius of 13 feet (approximately3.9 meters). This provides sufficient overlap of coverage in the aisle1120 for detection by the truck 1010 and provides ample distance for theexemplary truck 1010 to brake or otherwise come to a rest proximate tothe end of the aisle. In practice, other ranges may be utilized and maybe varied, based for example, upon the stopping requirements of thetruck 1010 and corresponding wireless remote control implementation, thesensing technology utilized and other suitable factors.

Referring to FIG. 18, a method 1200 of implementing the travel functionis illustrated. The method 1200 may be implemented, for example, by thecontroller 1103 on the truck 1010. As noted herein, the controller 1103may be responsive to receipt of a travel request from the remote controldevice 1070 to cause the truck 1010 to advance unless at least onecondition is satisfied. The method 1200 sets out various exemplaryvehicle conditions that may affect how the controller 1103 interpretstravel requests from the remote control device 1070.

The process waits to receive a travel request at 1202. If no travelrequest is received, the process continues to wait. If a travel requestis received, the process may either implement the travel request 1202 orperform optional checks or evaluations of vehicle conditions todetermine whether to acknowledge or otherwise implement the travelrequest, examples of which are illustrated at 1204, 1206, 1208 and 1210.

For example, the process may require that the truck 1010 is stoppedbefore recognizing a new travel request. This vehicle conditionrequirement may be implemented, for example, where the controller 1103limits the maximum amount of continuous travel of the vehicle withoutstopping while under wireless remote control in response to receipt ofthe first type (travel request) signal(s). In this regard, thecontroller 1103 may determine whether the truck 1010 is currentlystopped at 1204, e.g., using feedback from an encoder or other suitabledevice to detect motion of the truck. If the truck 1010 is not stopped,the process may optionally wait until the truck 1010 has come to rest orthe process may ignore or otherwise terminate evaluation of whether toimplement the received travel request as indicated by the dashed lines.

Moreover, the process may require that not only that the truck 1010 bestopped, but that there is no movement of the truck 1010 for apredetermined period of time. Thus, for example, if the truck 1010 isstopped, the process may determine whether a predetermined interval haspassed after detecting that the truck 1010 has come to rest at 1206. Ifthe predetermined interval has not passed, the process may wait untilthe predetermined interval has lapsed or the process may ignore orotherwise terminate processing of the received travel request asindicated by the dashed lines.

The process may also check at 1208 for vehicle conditions such asoperational and/or environmental conditions that would affect operationof the truck in response to a remote travel request. If the vehiclecondition check(s) indicate that it is okay to proceed processing thereceived travel request, then processing continues. Otherwise, theprocess may wait to resolve the condition, or the process may ignore orotherwise terminate processing of the received travel request asindicated by the dashed lines.

Operational and environmental conditions that may cause the process toignore or otherwise refuse to implement a travel request from the remotecontrol device 1070 may include factors such as detecting an operator onthe platform, detecting an object in the travel path of the truck 1010,detecting that the truck is in an area or location where wireless remotecontrol is not allowed, e.g., at the end of aisles or at intersectionssuch as by using the RFID tags described with reference to FIG. 17,detecting the lack of a pallet or other suitable carrier structure onthe forks of the truck, detecting that an invalid operator is loggedinto the truck and/or that the truck is paired with an unauthorizeduser, detecting that the power level of the received travel request isoutside a range, e.g., too weak indicating that the operator is out of apredetermined maximum range, or too strong, indicating that the operatoris too close to the truck 1010, etc. Thus, the operator may have towait, clear an obstacle, or otherwise remedy a condition before thetruck 1010 is ready to respond to remote travel requests.

The process may also check that a steer angle of the truck 1010 iswithin a predetermined range of steer angles at 1210. If the steeredwheel(s) of the truck 1010 are turned beyond the predetermined range,the steer angle may be corrected at 1212. Alternatively, the system maydefault the steered wheel to a predetermined position, e.g., steeredstraight or the system may ignore or otherwise terminate processing ofthe received travel request.

The truck 1010 is then moved forward at 1214. For example, if eachevaluated vehicle condition is satisfied by the controller as allowingremote travel, the controller causes the traction control system toadvance the truck 1010. The truck 1010 may also sound an alarm orprovide other forms of audible or visual cues when the truck 1010 istraveling in response to wireless remote control commands, or when thetravel control on the remote control device 1070 remains actuated, suchas by using the light source 1068 and/or the indicator such the strobelight 1072. As further illustrative examples, a horn and/or other cuemay be controlled by relays or other suitable switching devices to beactive concomitantly with engagement of the traction motor while thetruck 1010 operates in response to wireless remote control commands.

The process checks at 1216 to determine whether a predetermined stoppingevent has occurred. For example, the process may check to determinewhether the operator has deactivated the travel control on the remotecontrol device 1070. Upon deactivating the travel control, the truck1010 stops, e.g., by applying a brake, by coasting or by performingother suitable stopping operations. The process may also check at 1216to determine whether a predetermined time of travel, distance of travelor other like event has passed in response to movement of the vehicle inresponse to wireless remote control.

For example, the truck 1010 may be configured to travel a maximumdistance of continuous movement in response to a single wireless remotecontrol travel request. As another example, the truck 1010 may beconfigured to travel a maximum distance of continuous movement inresponse to repeated successive wireless remote control travel requests.An exemplary range may comprise a travel distance limited to 25-50 feet(approximately 7.6 meters to 15.2 meters). As another example, the truck1010 may be configured to travel for up to a predetermined maximumcontinuous travel time.

Other exemplary stopping events may comprise vehicle conditions, e.g.,as imposed by predefined travel limits, receiving a stop or disablecommand, detecting an obstacle in the travel path of the truck 1010,detecting a person on the truck 1010, detecting a change in the positionof the load carrying device (e.g., pallet, cage), detecting mechanical,electrical, pneumatic, hydraulic abnormal conditions of the truck, etc.If the predetermined stopping event is met at 1216, the truck 1010 isstopped or controlled to coast to a rest at 1218 and the system resets.If the operator issues a travel request from the wireless control device1070 before a given task is complete, the system may wait for thecurrent task to complete before issuing the next command.

According to various aspects of the present invention, the remotecontrol device 1070 may be a wearable wireless remote control devicethat is donned by the operator who is interacting with the truck 1010.In general, the wearable wireless remote control device 1070 maycomprise a wireless transmitter and a travel control, e.g., a button orswitch that is communicably coupled to the wireless transmitter. Asdescribed herein, actuation of the travel control causes the wirelesstransmitter to transmit a first type signal, which may request the truck1010 to advance in a first direction. Depending upon the particularimplementation, the wireless remote control device 1070 may furtherinclude a power pack such as a battery for powering the remote controldevice electronics, a control area where the travel control is locatedon the operator, e.g., on or about a hand of the operator and acommunications link between the transmitter and the control area wherethe transmitter is physically spaced from the control area when worn bythe operator.

If the travel request is properly received by the receiver 1102 and isdetermined to be a valid travel request, the truck 1010 may bewirelessly remotely controlled to travel for a prescribed time and/ordistance, and then enter a controlled brake or coast as described ingreater detail herein.

While the remote control device 1070 is illustrated in FIGS. 14 and 16as a glove garment that is worn by the operator around the wrist or arm,other configurations may alternatively be implemented. For example, theremote control device 1070 may be worn as a pendant around the neck ofthe operator, e.g., by looping the remote control device 1070 through asuitable lanyard, or the remote control device 1070 may be mounted onthe wrist or arm of an operator. Alternatively, the remote controldevice 1070 may be donned by clipping the remote control device 1070 toa shirt, belt, pants, vest, uniform or other piece of clothing using asuitable clip. Still further, the remote control device 1070 mayimplemented as a voice controlled transmitter, wherein the remotecontrol device 1070 may mount, for example, to a torso strap, sash orother suitable device. When used with such a voice control system of theremote control device 1070, operator voice commands such as TRAVEL,FORWARD, COAST, STOP, etc., may be used to cause the truck 1010 to movea preset distance and still maintain the heading set by the steercontroller 1112 (shown in FIG. 15), e.g., parallel to the storagelocations 1122 in the aisle 1120. The command words TRAVEL, FORWARD,COAST, STOP, etc., may be used to communicate with the traction motorcontroller 1106 while the steer controller 1112 automatically correctsitself to maintain a straight orientation or other desired heading. Theremote control device 1070 may further allow the operator to make minoradjustments to the heading of the truck 1010, e.g., by allowing voicecommands such as LEFT or RIGHT to adjust the heading of the truck 1010.Herein, translation of the voice commands into control commands for thetruck 1010 may be carried out either in the processor of the remotecontrol device 1070 or in the controller 1103 of the truck 1010.

Moreover, any of the disclosed configurations for the remote controldevice 1070 may be equipped with steering compensation controls. Forexample, the remote control device 1070 may include additional controlswithin the control area, such as a left steer button and a right steerbutton in addition to the travel button and optional stop or coastbutton. The amount of remotely controllable steer correction will likelydepend upon a number of factors such as environment of use, typicalanticipated correction, etc. However, in one exemplary arrangement,small steer angle corrections, e.g., on the order of 1 degree or lessmay be implemented for each actuation of the left and right steercontrols.

Further, the remote control system may be integrated with a steer anglecontrol of the truck 1010. The steer angle control is typicallyimplemented using a potentiometer, encoder or other suitable inputdevice, and may be positioned at any convenient location on the truck1010. When used in combination with additional steering controls, thesteer angle control sets a desired heading of the truck 1010. As anexample, an operator may line up the truck 1010 in an aisle parallel toa row of racks in a warehouse operation. Using angle sensing feedbackfrom the steer controller 1112 (shown in FIG. 15), the heading of thetruck 1010 may be maintained parallel to the racks as the truck 1010moves down the aisle. The steer angle control thus prevents drift of thetruck 1010 and maintains its course. Under this arrangement, a travelrequest from the remote control device 1070 causes the truck 1010 totravel substantially straight along a heading defined by the steercontroller.

A system that implements the jog control functionality set out hereinmay implement additional advanced features to satisfy specificperformance requirements. For example, the transmitters may be equippedwith a “global stop” command that shuts down all trucks 1010 withinrange of the transmitter that are operating under remote control. Thus,all receivers may be programmed or otherwise configured to recognize astop command, e.g., using a global or common command sequence. Moreover,the global stop command may be transmitted by appending an operator IDso that the identity of the operator who issues the global stop commandcan be identified.

In each of the illustrated exemplary systems, an antenna for thetransmitter could be located in a transmitter box, woven into thegarment, e.g., by integrating the antenna into Velcro, straps, bands, orother components associated with the transmitter, that is donned by theoperator, located in wiring between the transmitter box and controls,etc.

Still further, the transmitter may be directional. For example, a targetmay be provided on the truck 1010, e.g., as part of the receiver 1102 orantenna 1066. Thus, the operator must point the transmitter of theremote control device 1070 at or towards the target in order to causethe operation of the control, e.g., a jog command, to be received by thetruck 1010. Alternatively, certain commands may be non-directional,whereas other controls are directional. For example, the global stop(where provided) may not require detection by a target in order to beeffectuated. On the other hand, a control to initiate a jog operationmay be required to be detected by a suitable target. Targeted detectionmay be accomplished, for example, using infrared or other suitabletechnologies.

The numerous exemplary configurations of the remote control describedherein are presented by way of illustration and not by way of limitationof the manner in which a remote control may be configured. The variousdescribed features may be commingled into any desired configuration.Moreover, additional features may be provided in addition to, or in lieuof the features set out herein. Still further, the truck, remote controlsystem and/or components thereof, including the remote control device1070, may comprise any additional and/or alternative features orimplementations, examples of which are disclosed in U.S. ProvisionalPatent Application Ser. No. 60/825,688, filed Sep. 14, 2006 entitled“SYSTEMS AND METHODS OF REMOTELY CONTROLLING A MATERIALS HANDLINGVEHICLE;” U.S. patent application Ser. No. 11/855,310, filed Sep. 14,2007 entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING A MATERIALSHANDLING VEHICLE;” U.S. patent application Ser. No. 11/855,324, filedSep. 14, 2007 entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING AMATERIALS HANDLING VEHICLE;” U.S. Provisional Patent Application Ser.No. 61/222,632, filed Jul. 2, 2009, entitled “APPARATUS FOR REMOTELYCONTROLLING A MATERIALS HANDLING VEHICLE;” U.S. patent application Ser.No. 12/631,007, filed Dec. 4, 2009, entitled “MULTIPLE ZONE SENSING FORMATERIALS HANDLING VEHICLES;” U.S. Provisional Patent Application Ser.No. 61/119,952, filed Dec. 4, 2008, entitled “MULTIPLE ZONE SENSING FORREMOTELY CONTROLLED MATERIALS HANDLING VEHICLES;” U.S. ProvisionalPatent Application Ser. No. 61/234,866, filed Aug. 18, 2009, entitled“STEER CORRECTION FOR A REMOTELY OPERATED MATERIALS HANDLING VEHICLE;”U.S. patent application Ser. No. 12/649,738, filed Dec. 30, 2009,entitled “APPARATUS FOR REMOTELY CONTROLLING A MATERIALS HANDLINGVEHICLE;” U.S. patent application Ser. No. 12/649,815, filed Dec. 30,2009, entitled “STEER CORRECTION FOR A REMOTELY OPERATED MATERIALSHANDLING VEHICLE;” International Patent Application Serial No.PCT/US09/66789, filed Dec. 4, 2009, entitled “MULTIPLE ZONE SENSING FORMATERIALS HANDLING VEHICLES;” International Patent Application SerialNo. PCT/US09/69839, filed Dec. 30, 2009, entitled “APPARATUS FORREMOTELY CONTROLLING A MATERIALS HANDLING VEHICLE;” International PatentApplication Serial No. PCT/US09/69833, filed Dec. 30, 2009, entitled“STEER CORRECTION FOR A REMOTELY OPERATED MATERIALS HANDLING VEHICLE;”International Patent Application Serial No. PCT/US07/78455, filed Sep.14, 2007, entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING AMATERIALS HANDLING VEHICLE;” U.S. Pat. No. 7,017,689, issued Mar. 28,2006, entitled “ELECTRICAL STEERING ASSIST FOR MATERIAL HANDLINGVEHICLE;” and/or U.S. patent application Ser. No. 13/011,366, filed Jan.21, 2011 entitled “SYSTEMS AND METHODS OF REMOTELY CONTROLLING AMATERIALS HANDLING VEHICLE,” the entire disclosures of which are eachincorporated by reference herein.

Referring now to FIGS. 19 and 20, a materials handling vehicle 2010according to another aspect of the invention includes a load handlingassembly 2012, an operator's compartment 2013, and a power unit 2014.The load handling assembly 2012 includes a pair of forks 2016, each fork2016 having a load supporting wheel assembly 2018. The load handlingassembly 2012 may include other load handling features in addition to orin lieu of the illustrated arrangement of the forks 2016, such as a loadbackrest, scissors-type elevating forks, outriggers and separate heightadjustable forks, a mast, a load platform, collection cage or othersupport structure carried by the forks 2016 or otherwise provided forhandling a load supported and carried by the vehicle 2010.

As shown in FIGS. 19 and 20, the vehicle 2010 includes a first obstacledetector 2050 and a pair of second obstacle detectors 2052A and 2052Bmounted to the power unit 2014. The second obstacle detectors 2052A and2052B are spaced apart from each other along a horizontal axis H_(A) ofthe vehicle defining a horizontal direction, see FIG. 20. The firstobstacle detector 2050 is spaced apart from the second obstacledetectors 2052A and 2052B along a longitudinal axis V_(A) of the vehicle2010 defining a vertical direction, i.e., the second obstacle detectors2052A and 2052B are located below, i.e., closer to the ground, than thefirst obstacle detector 2050, see FIG. 19.

The first obstacle detector 2050 according to this aspect of theinvention may comprise a sweeping laser sensor capable of detectingobjects, for example, in first, second, and third zones Z₁, Z₂, Z₃ (alsoreferred to herein as scan zones or detection zones), which first,second, and third zones Z₁, Z₂, Z₃ may comprise planar zones, see FIGS.19 and 20. The second zone Z₂ may comprise a “stop zone”, and the firstand third zones Z₁ and Z₃ may comprise left and right “steer bumperzones”, such as the stop zone and the left and right steer bumper zonesdescribed in U.S. patent application Ser. No. 12/649,815, filed Dec. 30,2009, entitled “STEER CORRECTION FOR A REMOTELY OPERATED MATERIALSHANDLING VEHICLE, the entire disclosure of which is already incorporatedby reference herein. It is noted that the first obstacle detector 2050may be capable of detecting objects in additional or fewer zones thanthe three zones Z₁, Z₂, Z₃ illustrated.

The second obstacle detectors 2052A and 2052B according to this aspectof the invention may comprise point laser sensors that are capable ofdetecting objects between one or more of the zones Z₁, Z₂, Z₃ and thevehicle 2010, i.e., underneath one or more of the zones Z₁, Z₂, Z₃, asillustrated in FIG. 19, and are preferably capable of at least detectingobjects underneath the second zone Z₂. The second obstacle detectors2052A and 2052B are thus capable of detecting objects located in anon-detect zone DZ of the first obstacle detector 2050, see FIG. 19,i.e., which non-detect zone DZ is defined as an area below the zones Z₁,Z₂, Z₃ and thus not sensed by the first obstacle detector 2050. Hence,the first obstacle detector 2050 functions to detect objects locatedalong a path of travel of the power unit 2014 beyond the non-detect zoneDZ, while the second obstacle detectors 2052A and 2052B function tosense objects along the path of travel of the power unit 2014 in thenon-detect zone DZ, which is located just in front of the vehicle 2010,as shown in FIG. 19.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimiting to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiments were chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

Having thus described the invention of the present application in detailand by reference to preferred embodiments thereof, it will be apparentthat modifications and variations are possible without departing fromthe scope of the invention defined in the appended claims.

What is claimed is:
 1. A materials handling vehicle comprising: a powerunit; a load handling assembly; at least one first obstacle detectormounted at a first location on said power unit to detect an objectlocated along a path of travel of said power unit beyond a non-detectzone of said at least one first obstacle detector; and at least onesecond obstacle detector mounted at a second location on said powerunit, spaced from said first location in a first direction, and capableof detecting an object in said non-detect zone of said at least onefirst obstacle detector.
 2. The materials handling vehicle of claim 1,wherein said at least one first obstacle detector is located at a frontportion of said power unit.
 3. The materials handling vehicle of claim2, wherein said at least one second obstacle detector is spaced awayfrom said at least one first obstacle detector in a direction towardssaid load handling assembly.
 4. The materials handling vehicle of claim1, wherein said at least one first obstacle detector comprises asweeping laser sensor.
 5. The materials handling vehicle of claim 4,wherein said sweeping laser sensor is capable of detecting an object inany of first, second, and third zones, the first and third zonescomprising steer bumper zones used for implementing steer correctionmaneuvers and the second zone comprising a stop zone used for stoppingthe vehicle.
 6. The materials handling vehicle of claim 4, wherein saidat least one second obstacle detector comprises first and second pointlaser sensors spaced from one another in a second direction that isgenerally perpendicular to said first direction.
 7. The materialshandling vehicle of claim 6, wherein said first direction is a verticaldirection and said second direction is a horizontal direction.
 8. Thematerials handling vehicle of claim 1, wherein said first direction is ahorizontal direction.
 9. A materials handling vehicle comprising: apower unit; a load handling assembly; at least one first obstacledetector mounted at a first location on said power unit to detect anobject located in a scan zone along a path of travel of said power unitbeyond a non-detect zone of said at least one first obstacle detector,said non-detect zone being located between said scan zone of said firstobstacle detector and the vehicle; and at least one second obstacledetector mounted at a second location on said power unit spaced fromsaid first obstacle detector in a first direction and capable ofdetecting an object in said non-detect zone.
 10. The materials handlingvehicle of claim 9, wherein said at least one first obstacle detector islocated at a front portion of said power unit.
 11. The materialshandling vehicle of claim 10, wherein said at least one second obstacledetector is spaced away from said at least one first obstacle detectorin a direction towards said load handling assembly.
 12. The materialshandling vehicle of claim 9, wherein said at least one first obstacledetector comprises a sweeping laser sensor capable of detecting anobject in any of first, second, and third zones, the first and thirdzones comprising steer bumper zones used for implementing steercorrection maneuvers and the second zone comprising a stop zone used forstopping the vehicle.
 13. The materials handling vehicle of claim 9,wherein said at least one second obstacle detector comprises first andsecond point laser sensors spaced from said sweeping laser sensor in avertical direction and spaced from one another in a horizontaldirection.
 14. The materials handling vehicle of claim 9, wherein saidnon-detect zone is located just in front of the vehicle and underneathsaid scan zone of said at least one first obstacle detector.
 15. Thematerials handling vehicle of claim 9, wherein said first direction is ahorizontal direction
 16. A materials handling vehicle comprising: apower unit; a load handling assembly; at least one first obstacledetector comprising a sweeping laser sensor mounted at a first locationon said power unit to detect an object located in a scan zone along apath of travel of said power unit beyond a non-detect zone of said atleast one first obstacle detector; and at least one second obstacledetector mounted on said power unit below said at least one firstobstacle detector and capable of detecting an object in said non-detectzone underneath said scan zone of said at least one first obstacledetector.
 17. The materials handling vehicle of claim 16, wherein saidsweeping laser sensor is capable of detecting an object in any of first,second, and third zones, the first and third zones comprising steerbumper zones used for implementing steer correction maneuvers and thesecond zone comprising a stop zone used for stopping the vehicle. 18.The materials handling vehicle of claim 16, wherein said at least onesecond obstacle detector comprises first and second point laser sensorsspaced from one another in a horizontal direction.
 19. The materialshandling vehicle of claim 16, wherein said non-detect zone is locatedjust in front of the vehicle and underneath said scan zone of saidsweeping laser sensor.
 20. The materials handling vehicle of claim 19,wherein said scan zone of said sweeping laser sensor is oriented at anangle from said first location toward a floor surface.
 21. A materialshandling vehicle comprising: a power unit; a load handling assemblycoupled to said power unit; at least one obstacle detector mounted tosaid power unit to detect an object located along a path of travel ofsaid power unit, said detector generating a distance signal upondetecting an object corresponding to a distance between the detectedobject and said power unit; and a controller receiving said distancesignal and generating a corresponding vehicle stop or maximum allowablespeed signal based on said distance signal.
 22. The materials handlingvehicle as set out in claim 21, further comprising a load sensor togenerate a weight signal indicative of a weight of a load on said loadhandling assembly.
 23. The materials handling vehicle as set out inclaim 22, wherein said controller receives said distance signal and saidweight signal and generates a corresponding vehicle stop or maximumallowable speed signal based on said distance and weight signals. 24.The materials handling vehicle as set out in claim 23, wherein for agiven first load weight, if a sensed object is located at a distancewithin a first detection zone, a stop signal is generated by saidcontroller to effect stopping of said vehicle.
 25. The materialshandling vehicle as set out in claim 24, wherein for said given firstload weight, if a sensed object is located at a distance within a seconddetection zone spaced further away from said power unit than said firstdetection zone, then a first maximum allowable vehicle speed is definedcorresponding to said first load weight and an object being detected insaid second detection zone.
 26. The materials handling vehicle as setout in claim 25, wherein for said given first load weight, if a sensedobject is located at a distance within a third detection zone spacedfurther away from said power unit than said first and second detectionzones, then a second maximum allowable vehicle speed greater than saidfirst maximum is defined corresponding to said first load weight and anobject being detected in said third detection zone.
 27. A materialshandling vehicle comprising: a power unit; a load handling assemblycoupled to said power unit; at least one obstacle detector mounted tosaid power unit to detect an object located along a path of travel ofsaid power unit, said detector generating a distance signal upondetecting an object corresponding to a distance between the detectedobject and said power unit; a load sensor to generate a weight signalindicative of a weight of a load on said load handling assembly; and acontroller receiving said distance signal and said weight signal andgenerating a corresponding vehicle stop or maximum allowable speedsignal based on said distance and weight signals.
 28. The materialshandling vehicle as set out in claim 27, wherein for a given first loadweight, if a sensed object is located at a distance within a firstdetection zone, a stop signal is generated by said controller to effectstopping of said vehicle.
 29. The materials handling vehicle as set outin claim 28, wherein for said given first load weight, if a sensedobject is located at a distance within a second detection zone spacedfurther away from said power unit than said first detection zone, then afirst maximum allowable vehicle speed is defined corresponding to saidfirst load weight and an object being detected in said second detectionzone.
 30. The materials handling vehicle as set out in claim 29, whereinfor said given first load weight, if a sensed object is located at adistance within a third detection zone spaced further away from saidpower unit than said first and second detection zones, then a secondmaximum allowable vehicle speed greater than said first maximum isdefined corresponding to said first load weight and an object beingdetected in said third detection zone.